Soil quality - Determination of trace elements in extracts of soil by inductively coupled plasma - atomic emission spectrometry (ICP - AES)

This International Standard describes the determination of trace elements in digests or extraction solutions
from soil by inductively coupled plasma - atomic emission spectrometry (ICP-AES) for 34 elements (see
Table 1).
This multi-element determination method is applicable to soil extracts obtained with aqua regia in accordance
with ISO 11466, with DTPA in accordance with ISO 14870 or other weak extractants, or soil extracts for the
determination of total element contents using the acid digestion method of ISO 14869-1 or the fusion method
of ISO 14869-2.
The choice of calibration method depends on the extractant and can be adapted to the extractant
concentration.

Qualité du sol - Dosage des éléments traces dans des extraits de sol par spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES)

L'ISO 22036:2008 d�crit le dosage d'�l�ments traces dans des solutions de digestion ou des solutions d'extraction du sol par spectrom�trie d'�mission atomique avec plasma induit par haute fr�quence (ICP-AES) pour 34 �l�ments.
Cette m�thode de dosage multi�l�ments est applicable aux extraits de sol obtenus avec de l'eau r�gale conform�ment � l'ISO 11466, avec une solution DTPA conform�ment � l'ISO 14870, ou avec d'autres agents d'extraction faibles, ou aux extraits de sols destin�s � �tre utilis�s pour le dosage des teneurs �l�mentaires totales au moyen de la m�thode de digestion par voie acide de l'ISO 14869‑1 ou de la m�thode par fusion de l'ISO 14869‑2.
Le choix de la m�thode d'�talonnage d�pend de l'agent d'extraction et peut �tre adapt� � la concentration en agent d'extraction.

Kakovost tal - Določevanje elementov v sledovih z atomsko emisijsko spektrometrijo z induktivno sklopljeno plazmo (ICP-AES)

Ta mednarodni standard opisuje določevanje elementov v sledovih v razklopih ali ekstrakcijskih raztopinah tal z induktivno sklopljeno plazmo – atomsko emisijsko spektrometrijo (ICP-AES) za 34 elementov (glej preglednico 1).
Ta metoda določevanja z več elementi se uporablja za ekstrakte tal, pridobljene z zlatotopko v skladu s standardom ISO 11466, z DTPA v skladu s standardom ISO 14870 ali drugimi šibkimi ekstrakcijskimi sredstvi ali ekstrakti tal za določevanje skupnih vsebnosti elementov z metodo razklopa v kislini iz standarda ISO 14869-1 ali metodo raztapljanja iz standarda ISO 14869-2.
Izbira metode umerjanja je odvisna od ekstrakcijskega sredstva in jo je mogoče prilagoditi koncentraciji
ekstrakcijskega sredstva.

General Information

Status
Published
Public Enquiry End Date
03-Jun-2019
Publication Date
03-Sep-2019
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
30-Aug-2019
Due Date
04-Nov-2019
Completion Date
04-Sep-2019

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INTERNATIONAL ISO
STANDARD 22036
First edition
2008-12-15
Soil quality — Determination of trace
elements in extracts of soil by inductively
coupled plasma - atomic emission
spectrometry (ICP-AES)
Qualité du sol — Dosage des éléments traces dans des extraits de sol
par spectrométrie d'émission atomique avec plasma induit par haute
fréquence (ICP-AES)
Reference number
ISO 22036:2008(E)
ISO 2008
---------------------- Page: 1 ----------------------
ISO 22036:2008(E)
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© ISO 2008

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Published in Switzerland
ii © ISO 2008 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22036:2008(E)
Contents Page

Foreword ............................................................................................................................................................iv

1 Scope......................................................................................................................................................1

2 Normative references............................................................................................................................1

3 Terms and definitions ...........................................................................................................................2

4 Principle..................................................................................................................................................3

5 Interferences ..........................................................................................................................................6

5.1 General ...................................................................................................................................................6

5.2 Spectral interferences...........................................................................................................................6

5.3 Non-spectral interferences...................................................................................................................7

6 Reagents.................................................................................................................................................8

7 Instrumentation .....................................................................................................................................9

8 Procedure.............................................................................................................................................10

8.1 Cleaning of glassware.........................................................................................................................10

8.2 Instrument performance parameters.................................................................................................10

8.3 Instrument optimization......................................................................................................................11

8.4 Alignment of the spectrometer ..........................................................................................................11

8.5 Calibration methods............................................................................................................................12

8.6 Solutions to be prepared ....................................................................................................................12

8.7 Measurement procedure.....................................................................................................................13

9 Calculation of results..........................................................................................................................14

10 Precision...............................................................................................................................................14

11 Expression of results..........................................................................................................................14

12 Test report............................................................................................................................................15

Annex A (informative) Repeatability and precision results ..........................................................................16

Annex B (informative) Interferences ...............................................................................................................19

Bibliography......................................................................................................................................................30

© ISO 2008 – All rights reserved iii
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ISO 22036:2008(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 22036 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical

methods and soil characteristics.
iv © ISO 2008 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 22036:2008(E)
Soil quality — Determination of trace elements in extracts of
soil by inductively coupled plasma - atomic emission
spectrometry (ICP-AES)

WARNING — The procedures in this International Standard should be carried out by competent,

trained persons. Some of the techniques and reagents, including the use of equipment, are potentially

very dangerous. Users of this International Standard who are not thoroughly familiar with the potential

dangers and related safe practices should take professional advice before commencing any operation.

1 Scope

This International Standard describes the determination of trace elements in digests or extraction solutions

from soil by inductively coupled plasma - atomic emission spectrometry (ICP-AES) for 34 elements (see

Table 1).

This multi-element determination method is applicable to soil extracts obtained with aqua regia in accordance

with ISO 11466, with DTPA in accordance with ISO 14870 or other weak extractants, or soil extracts for the

determination of total element contents using the acid digestion method of ISO 14869-1 or the fusion method

of ISO 14869-2.

The choice of calibration method depends on the extractant and can be adapted to the extractant

concentration.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.

ISO Guide 32, Calibration in analytical chemistry and use of certified reference materials

ISO 3696, Water for analytical laboratory use — Specification and test methods

ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results — Part 1: General

principles and definitions

ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method

for the determination of repeatability and reproducibility of a standard measurement method

ISO 11465, Soil quality — Determination of dry matter and water content on a mass basis — Gravimetric

method
ISO 11466, Soil quality — Extraction of trace elements soluble in aqua regia

ISO 14869-1, Soil quality — Dissolution for the determination of total element content — Part 1: Dissolution

with hydrofluoric and perchloric acids

ISO 14869-2, Soil quality — Dissolution for the determination of total element content — Part 2: Dissolution by

alkaline fusion
ISO 14870, Soil quality — Extraction of trace elements by buffered DTPA solution
© ISO 2008 – All rights reserved 1
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ISO 22036:2008(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5725-1, ISO 5725-2, ISO Guide 32

and the following apply.
3.1
analyte
element to be determined
3.2
blank calibration solution

solution prepared in the same way as the calibration solution but leaving out the analytes

3.3
blank test solution

solution prepared in the same way as the test sample solution but omitting the test portion

3.4
calibration solution

solution used to calibrate the instrument, prepared from stock solutions by adding acids, buffer, reference

element and salts as needed
3.5
instrument detection limit

lowest concentration that can be detected with a defined statistical probability using a clean instrument and a

clean solution
NOTE The clean solution is usually dilute nitric acid.
3.6
laboratory sample
sample sent to the laboratory for analysis
3.7
linearity

straight-line relationship between the mean result of measurement and the quantity (concentration) of the

analyte
3.8
method detection limit

lowest concentration that can be detected using a specific analytical method with a defined statistical

probability for defined maximum matrix element concentrations
3.9
pure chemical
chemical with the highest available purity and known stoichiometry

NOTE The content of analyte and contaminants should be known with an established degree of certainty.

3.10
stock solution

solution with accurately known analyte concentration(s), prepared from pure chemicals (3.9)

NOTE Stock solutions are reference materials within the meaning of ISO Guide 30.
3.11
test sample

portion taken from the laboratory sample after homogenizing, grinding, dividing, etc.

2 © ISO 2008 – All rights reserved
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ISO 22036:2008(E)
3.12
test sample solution

solution prepared after extraction or dissolution of the test sample according to appropriate specifications

NOTE The test sample solution is intended for use for measurement.
4 Principle

Inductively coupled plasma - atomic emission spectrometry (ICP-AES) can be used to determine trace

elements in solution. The solution is dispersed by a suitable nebulizer and the resulting aerosol is transported

into the plasma torch. In a radio-frequency inductively coupled plasma the solvent is evaporated, the dried

salts are then vaporized, dissociated, atomized and ionized. The atoms or ions are excited thermally and the

number of photons emitted during transition to a lower energy level are measured with optical emission

spectrometry. The spectra are dispersed by a grating spectrometer, and the intensities of the emission lines

are monitored by photosensitive devices. The identification of the element takes place by means of the

wavelength of the radiation (energy of photons), while the concentration of the element is proportional to the

intensity of the radiation (number of photons). The ICP-AES method can be used to perform multi-element

determinations using sequential or simultaneous optical systems and axial or radial viewing of the plasma.

Table 1 shows examples of recommended wavelengths, and detection limits for one particular instrument.

Data given are valid for water acidified with nitric acid with an optimized instrument. Using other instruments

can lead to different detection limits. Adoption of other wavelengths is possible.

Table 1 — Recommended wavelengths and estimated detection limits for selected elements and

[9]

wavelengths obtained using ICP-AES Varian, Vista-MPX megapixel (CD detector features)

Element wavelengths and analytical lines Axial viewing Radial viewing

Element Wavelength Lines Detection limit Detection limit Detection limit Detection limit

a b a b
nm I = atom µg/l mg/kg µg/l mg/kg
II = ion
Aluminium 396,068 1 0,10 4 0,4
308,215 I 2,6 0,26
309,271 I
396,152 I 0,1 0,01 4 0,4
167,078 l 0,3 0,03 1 0,1
Antimony 206,833 I 0,5 0,5 16 1,6
217,581 I 1,8 0,18 5 0,5
231,146 l 2 0,2
Arsenic 188,979 2 0,2 12 1,2
193,696 1 0,1 11 1,1
197,198 I 5 0,5
189,042 l
188,979 l 1,5 0,15 5 0,5
Barium 233,527 II 0,06 0,006 0,7 0,07
455,403 II 0,01 0,001 0,15 0,02
493,409 II 0,04 0,004 0,15 0,02
Beryllium 313,107 II 0,03 0,003 0,15 0,02
313,402 II 0,01 0,001 0,15 0,02
234,861 II 0,01 0,001 0,05 0,005
Bismuth 223,061 I 1,8 0,18 6 0,6
306,771 l 17 1,7
315,887
Boron 208,959 I 0,7 0,07 1,2 0,12
249,678 I 1,1 0,11 1,5 0,15
249,772 l 0,5 0,05 1 0,1
© ISO 2008 – All rights reserved 3
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ISO 22036:2008(E)
Table 1 (continued)
Element wavelengths and analytical lines Axial viewing Radial viewing

Element Wavelength Lines Detection limit Detection limit Detection limit Detection limit

a b a b
nm I = atom µg/l mg/kg µg/l mg/kg
II = ion
Cadmium 214,438 II 0,1 0,01 0,5 0,05
226,502 II 0,11 0,011 0,6 0,06
228,802 II 0,20 0,02 0,5 0,05
Calcium 396,847 II 0,5 0,05 0,3 0,03
317,933 II 0,3 0,03 6,5 0,7
393,366 II 0,5 0,05
Chromium 267,716 II 0,1 0,01 1 0,1
205,552 II 0,3 0,03
206,149 II
283,563 II 0,2 0,02
284,325 II
Cobalt 238,892 II 0,4 0,04 1,2 0,1
0,4 0,04 1 0,1
228,616 II
230,786 II
Copper 327,396 I 0,3 0,03 1,5 0,1
224,700 II
324,754 I 0,6 0,06
Iron 238,204 II 0,3 0,03 0,9 0,09
239,562 II
259,940 II 0,5 0,05 0,7 0,07
Lead 220,353 II 0,4 0,04 8 0,8
216,999 I
224,688 I
261,418 I
283,306 I 1,8 0,18
Lithium 670,783 I 1,7 0,17 1 0,1
460,286 I 67 6,7
Magnesium 279,553 II 0,02 0,002 0,1 0,01
279,079 II 1 0,1 4 0,4
285,213 I 0,06 0,006 0,25 0,025
279,806 II 1,5 0,15 10 1
Manganese 257,610 II 0,10 0,01 0,13 0,01
260,569 II
279,482 II
293,306 II 0,4 0,04 1 0,1
403,076 I 0,8 0,08
259,372 ll 0,05 0,005
Mercury 194,227 II 1,2 0,12 2,5 0,25
1 0,1 2 0,20
253,652 I
184,890 I
Molybdenum 202,030 II 0,2 0,02 2 0,2
204,598 II 0,6 0,06 3 0,3
Nickel 231,604 II 0,4 0,04 2,1 0,2
221,647 II 0,3 0,03 1,4 0,14
216,555 I 0,15 0,015
232,003 ll
Phosphorus 177,428 I 1,5 0,15 25 2,5
178,222 I 7 0,7
213,618 I 1,3 0,13 5,3 0,53
214,914 l 1 0,1 11 1,1
4 © ISO 2008 – All rights reserved
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ISO 22036:2008(E)
Table 1 (continued)
Element wavelengths and analytical lines Axial viewing Radial viewing

Element Wavelength Lines Detection limit Detection limit Detection limit Detection limit

a b a b
nm I = atom µg/l mg/kg µg/l mg/kg
II = ion
Potassium 766,491 I 0,2 0,02 4 0,4
769,896 I 23 2,3 12 1,2
Rubidium 780,03 I 1 0,1 5 0,5
Selenium 196,026 I 0,8 0,08 16 1,6
203,985 I 2,8 0,28
Silicon 251,611 I 0,9 0,09 2,2 0,22
212,412 I 1,3 0,13 5 0,5
288,158 I 1 0,1
Silver 328,068 I 0,4 0,04 1 0,1
338,289 I 1 0,1 2 0,2
Sodium 589,592 I 0,6 0,06 1,5 0,2
588,995 I 12 1,2 15 0,15
330,237 I 69 6,9
Strontium 407,771 II 0,01 0,001 0,1 0,01
421,552 II 0,01 0,001 0,1 0,01
460,733 I 0,3 0,03
Sulfur 181,962 I 4 0,4 13 1,3
182,036
Thallium 190,800 II 2 0,2 13 0,1
190,864 II
Tin 189,933 II 6 0,6 8 0,8
235,484 I 23 2,3 20 2,0
283,998 l 11
Titanium 336,121 II 0,15 0,015 1 0,1
334,941 II 0,2 0,02 0,25 0,25
337,280 II 0,2 0,02 1 0,1
Vanadium 292,402 II 0,3 0,03 2 0,2
309,310 II 0,08 0,008
311,837 II 0,1 0,01
290,882 ll
310,230 ll
Zinc 213,856 I 0,05 0,005 0,8 0,08
202,548 II 0,03 0,003 0,7 0,07
206,200 ll 0,15 0,015 2 0,02
Typical 3-sigma detection limits using 30 s integration time.

The detection limit (LOD), as a mass fraction of the soil sample in mg/kg dry matter, is given assuming that a test sample of 1 g is

extracted and diluted to 100 ml. The LOD shown in Table 1 are only examples of a given equipment and laboratory conditions. Each

laboratory shall select appropriate wavelengths and determine LOD under its specific laboratory conditions.

NOTE The wavelengths given in Table 1 are often used, but they are given here only as an example. Adoption of

other wavelengths is possible. The limit of detection and the linear range vary for each element with the wavelength,

spectrometer, operating conditions and matrix load in the sample solution. If solutions with high salt concentrations (typical

for soil extract solutions) are measured, the LOD is substantially increased compared with water samples.

© ISO 2008 – All rights reserved 5
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ISO 22036:2008(E)

This International Standard refers specifically to the use of inductively coupled plasma - atomic emission

spectrometry. Users of this International Standard are advised to operate their laboratories to accepted quality

control procedures. Certified Reference Materials (CRM) should be used to establish the amounts of the

relevant elements in in-house reference materials. The latter can be used for routine quality control of the

procedures given in this International Standard.

Results shall be established with control charts, for each element, within the laboratory. No result shall be

accepted which falls outside an agreed limit. Quality control procedures based on widely accepted statistical

techniques shall be used to establish such limits, that these are stable and that no long-term drift is occurring.

Certified Reference Materials should be used regularly to maintain the integrity of the in-house reference

materials and, thereby, the quality control system.
5 Interferences
5.1 General

The presence of different matrix elements in the sample solution can cause severe interferences, which result

in systematic errors of the analyte signal. Special techniques, e.g. background correction, matrix matching of

the calibration solution or the standard addition technique, can be used to compensate such interferences.

Interferences are classified into spectral and non-spectral interferences. They can be specific for an analyte or

non-specific.

Spectral interferences (see 5.2) are due to incomplete isolation of the radiation emitted by the analyte from

other radiation sources detected and amplified by the detection system (additive interferences).

Non-spectral interferences (see 5.3) are interferences where the sensitivity changes due to the composition of

the solutions to be measured (multiplicative interferences). The observed matrix effect is a composite

interference due to all of the components in the sample solution.

Background correction is required for trace element determination. Background emission shall be measured

adjacent to analyte lines on samples during analysis. The position selected for the background-intensity

measurement, on one or both sides of the analytical line, is determined by the complexity of the spectrum

adjacent to the analyte line. The position used should be as free as possible from spectral interference, and

should reflect the same change in background intensity as occurs at the analyte wavelength measured.

Increase in background is more intensive with axial-view instruments. Background correction is not required in

cases of line broadening, where the analytical result is actually degraded by a background correction

measurement.
5.2 Spectral interferences
Spectral interferences are, e.g.

⎯ partially or complete overlap of an emission line of another element with that of the analyte; special case:

increase of background caused by a wing of a strong emission line located nearby, e.g. sloping

background shift at Pb 220,353 nm caused by Al 220,463 nm,

⎯ overlap of a molecular band from a multi-atomic particle formed in the plasma from the solvent, the

ambient air or the gases (e.g. N , NO, NH, OH, CN) with the emission line of an analyte,

⎯ background increase caused by recombination phenomena, e.g. continuum emitted by Al between

190 nm to 220 nm,
⎯ increase of background caused by stray light.
6 © ISO 2008 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 22036:2008(E)

A spectral line overlap usually leads to the choice of an alternative line. If this is not possible, mathematical

correction procedures (e.g. inter-element correction technique, multi-component spectral fitting) can be used

to compensate the interference. A parallel background shift can be compensated by background correction.

To correct a sloping background shift, two background correction points on each side of the peak are used.

For the investigation of spectral interferences of aqua regia extracts of soil, the most prominent lines of the

analytes As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Tl and Zn were used. The most important soil elements Al, As, Ca,

Cr, Cu, Co, Cu, Fe, Mg, Mn, Mo, Ni, Ti, V and Zn were used as interference elements in two concentrations:

100 mg/l and 500 mg/l. These element concentrations are equal to 0,33 % and 1,67 % (mass fraction) in soils,

for aqua regia extraction carried out in accordance with ISO 11466.

Tables B.1 and B.3 in Annex B give a summary of potential spectral interferences when analysing aqua regia

extracts of soils. Both the interfering elements and the emission line of these elements are given. A Perkin-

Elmer Optima 3000 instrument with a spectral resolution of 0,006 nm at 200 nm was employed for the study

for Table B.1, and a Varian Vista-PRO with axial plasma for Table B.3. Line coincidences, which are

dependent on the spectral resolution of the spectrometer, only become perceptible when the concentration of

the interfering element and analyte reach a critical level.

In Table B.2 the interference is expressed as analyte concentration equivalents (i.e. false positive increase of

analyte concentrations) arising from 100 mg/l and 500 mg/l of the interfering element, respectively. The data

are intended as a guide for indicating the extent of potential interference. The user should be aware that other

instruments may exhibit somewhat different levels of interference than those shown in Table B.2, because the

intensities vary with instrument construction and operating conditions, such as power, introduction gas flow

rate, and observation height.

Some potential spectral interferences observed for the recommended wavelengths using an axial viewing

instrument are given in Table B.3. For example, if Cr is to be determined at 267,716 nm in a sample

containing approximately 100 mg/l of Al, a false positive signal is observed for a Cr level equivalent to

approximately 0,06 mg/l. The user should take into account that other instruments may exhibit levels of

interference somewhat different from those shown in Table B.3. The interference effects shall be evaluated for

each individual instrument, whether configured as a sequential or simultaneous instrument. For each

instrument, intensities vary not only with optical resolution but also with operating conditions (such as power,

viewing height and argon flow rate). When using the recommended wavelengths, the analyst is required to

determine and document for each wavelength the effect from referenced interferences (see Table B.3) as well

as any other suspected interferences that may be specific to the instrument or matrix. The analyst should use

a computer routine for automatic correction on all analysis.
5.3 Non-spectral interferences

Non-spectral interferences can occur during nebulization or sample introduction (physical nature) or in the

plasma itself (both physical and chemical natures).

Transport interferences are due to differences in the physical properties (viscosity, surface tension, density)

between the sample solutions and the calibration solutions. They are caused by differences in the dissolved

solid content (e.g. salts, organic substances) as well as in the type or concentration of acid. As a consequence,

the supply of solution to the nebulizer, the efficiency of nebulization and the droplet size distribution of the

aerosol are altered, and hence the sensitivity changes. Errors due to these interferences can be overcome by

dilution of the solutions, by matrix matching, by standard addition or by the reference element technique

(internal standardization).

1) Perkin-Elmer Optima 3000 and Varian Vista-Pro are examples of suitable products available commercially. This

information is given for the convenience of users of this document and does not constitute an endorsement by ISO of

these products.
© ISO 2008 – All rights reserved 7
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ISO 22036:2008(E)

Excitation interferences cause changes in the sensitivity as a result of changed plasma conditions due to

introduction of the matrix. These changes are attributed to a change in the excitation conditions in the plasma

caused by easily ionizable elements like alkali metals. Enhancement or depressant effect of easily ionizable

elements on analyte emission depends on the operating conditions of the plasma (e.g. power, sample

introduction gas flow rate, observation height), and differ from element to element. Improvement of the plasma

conditions can therefore reduce excitation interferences. Other possibilities are dilution of the solutions, matrix

matching or the standard addition technique.
6 Reagents
All reagents shall be of recognized analytical grade.
6.1 Water.

Use demineralized water or water distilled from an all-glass apparatus, conforming to Grade 2 of ISO 3696.

The water used for blank determinations, and for preparing reagents and standard solutions, shall have

element concentrations that are negligible compared with the lowest concentration to be determined in the

sample solutions.

An example of reagents used for aqua regia extractions in accordance with ISO 11466 is given in the following.

Reagents based on other International Standards or other documents should be prepared accordingly.

6.2 Nitric acid, w(HNO ) = 65 %; ~ 1,40 g/ml.
The same batch of nitric acid shall be used throughout the procedure.
6.3 Nitric acid (1+1).
Add 500 ml nitric acid (6.2) to 400 ml water, mix and dilute to 1 l.
6.4 Hydrochloric acid, w(HCl) = 37 %; ~ 1,18 g/ml.
The same batch of hydrochloric acid shall be used throughout the procedure.
6.5 Hydrochloric acid (1+1).
Add 500 ml hydrochloric acid (6.4) to 400 ml water (6.1), mix and dilute to 1 l.

Other reagents used for dissolution or extraction of soil samples are described in the relevant standards.

6.6 Preparation of stock solutions and standard solutions of individual elements.

Two sources of stock solutions are available:
⎯ commercially available stock solutions;

⎯ stock solutions prepared in the laboratory from pure elements or stoichiometrically defined salts or oxides.

The concentrations of single-element solutions are 1 000 mg/l.

NOTE Commercially available stock solutions have the advantage that they remove the need to handle directly toxic

metals, especially thallium. However, special care needs to be taken that these solutions are supplied with a certified

composition from a reputable source and are checked on a regular basis.
6.7 Intermediate standard solutions.

Intermediate standard solutions may be prepared for each individual analyte, or for multi-element standard

solutions by dilution of stock solutions. These solutions should be stabilized by adding 10 ml nitric acid (6.3) to

100 ml of solution. The intermediate solutions have only limited stability and should be discarded after three

months, depending on the solution concentration.
8 © ISO 2008 – All rights reserved
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ISO 22036:2008(E)
...

SLOVENSKI STANDARD
SIST ISO 22036:2019
01-oktober-2019
Kakovost tal - Določevanje elementov v sledovih z atomsko emisijsko
spektrometrijo z induktivno sklopljeno plazmo (ICP-AES)

Soil quality - Determination of trace elements in extracts of soil by inductively coupled

plasma - atomic emission spectrometry (ICP - AES)

Qualité du sol - Dosage des éléments traces dans des extraits de sol par spectrométrie

d'émission atomique avec plasma induit par haute fréquence (ICP-AES)
Ta slovenski standard je istoveten z: ISO 22036:2008
ICS:
13.080.10 Kemijske značilnosti tal Chemical characteristics of
soils
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
SIST ISO 22036:2019 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 22036:2019
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SIST ISO 22036:2019
INTERNATIONAL ISO
STANDARD 22036
First edition
2008-12-15
Soil quality — Determination of trace
elements in extracts of soil by inductively
coupled plasma - atomic emission
spectrometry (ICP-AES)
Qualité du sol — Dosage des éléments traces dans des extraits de sol
par spectrométrie d'émission atomique avec plasma induit par haute
fréquence (ICP-AES)
Reference number
ISO 22036:2008(E)
ISO 2008
---------------------- Page: 3 ----------------------
SIST ISO 22036:2019
ISO 22036:2008(E)
PDF disclaimer

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COPYRIGHT PROTECTED DOCUMENT
© ISO 2008

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
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Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2008 – All rights reserved
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SIST ISO 22036:2019
ISO 22036:2008(E)
Contents Page

Foreword ............................................................................................................................................................iv

1 Scope......................................................................................................................................................1

2 Normative references............................................................................................................................1

3 Terms and definitions ...........................................................................................................................2

4 Principle..................................................................................................................................................3

5 Interferences ..........................................................................................................................................6

5.1 General ...................................................................................................................................................6

5.2 Spectral interferences...........................................................................................................................6

5.3 Non-spectral interferences...................................................................................................................7

6 Reagents.................................................................................................................................................8

7 Instrumentation .....................................................................................................................................9

8 Procedure.............................................................................................................................................10

8.1 Cleaning of glassware.........................................................................................................................10

8.2 Instrument performance parameters.................................................................................................10

8.3 Instrument optimization......................................................................................................................11

8.4 Alignment of the spectrometer ..........................................................................................................11

8.5 Calibration methods............................................................................................................................12

8.6 Solutions to be prepared ....................................................................................................................12

8.7 Measurement procedure.....................................................................................................................13

9 Calculation of results..........................................................................................................................14

10 Precision...............................................................................................................................................14

11 Expression of results..........................................................................................................................14

12 Test report............................................................................................................................................15

Annex A (informative) Repeatability and precision results ..........................................................................16

Annex B (informative) Interferences ...............................................................................................................19

Bibliography......................................................................................................................................................30

© ISO 2008 – All rights reserved iii
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SIST ISO 22036:2019
ISO 22036:2008(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 22036 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical

methods and soil characteristics.
iv © ISO 2008 – All rights reserved
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SIST ISO 22036:2019
INTERNATIONAL STANDARD ISO 22036:2008(E)
Soil quality — Determination of trace elements in extracts of
soil by inductively coupled plasma - atomic emission
spectrometry (ICP-AES)

WARNING — The procedures in this International Standard should be carried out by competent,

trained persons. Some of the techniques and reagents, including the use of equipment, are potentially

very dangerous. Users of this International Standard who are not thoroughly familiar with the potential

dangers and related safe practices should take professional advice before commencing any operation.

1 Scope

This International Standard describes the determination of trace elements in digests or extraction solutions

from soil by inductively coupled plasma - atomic emission spectrometry (ICP-AES) for 34 elements (see

Table 1).

This multi-element determination method is applicable to soil extracts obtained with aqua regia in accordance

with ISO 11466, with DTPA in accordance with ISO 14870 or other weak extractants, or soil extracts for the

determination of total element contents using the acid digestion method of ISO 14869-1 or the fusion method

of ISO 14869-2.

The choice of calibration method depends on the extractant and can be adapted to the extractant

concentration.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.

ISO Guide 32, Calibration in analytical chemistry and use of certified reference materials

ISO 3696, Water for analytical laboratory use — Specification and test methods

ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results — Part 1: General

principles and definitions

ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method

for the determination of repeatability and reproducibility of a standard measurement method

ISO 11465, Soil quality — Determination of dry matter and water content on a mass basis — Gravimetric

method
ISO 11466, Soil quality — Extraction of trace elements soluble in aqua regia

ISO 14869-1, Soil quality — Dissolution for the determination of total element content — Part 1: Dissolution

with hydrofluoric and perchloric acids

ISO 14869-2, Soil quality — Dissolution for the determination of total element content — Part 2: Dissolution by

alkaline fusion
ISO 14870, Soil quality — Extraction of trace elements by buffered DTPA solution
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3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5725-1, ISO 5725-2, ISO Guide 32

and the following apply.
3.1
analyte
element to be determined
3.2
blank calibration solution

solution prepared in the same way as the calibration solution but leaving out the analytes

3.3
blank test solution

solution prepared in the same way as the test sample solution but omitting the test portion

3.4
calibration solution

solution used to calibrate the instrument, prepared from stock solutions by adding acids, buffer, reference

element and salts as needed
3.5
instrument detection limit

lowest concentration that can be detected with a defined statistical probability using a clean instrument and a

clean solution
NOTE The clean solution is usually dilute nitric acid.
3.6
laboratory sample
sample sent to the laboratory for analysis
3.7
linearity

straight-line relationship between the mean result of measurement and the quantity (concentration) of the

analyte
3.8
method detection limit

lowest concentration that can be detected using a specific analytical method with a defined statistical

probability for defined maximum matrix element concentrations
3.9
pure chemical
chemical with the highest available purity and known stoichiometry

NOTE The content of analyte and contaminants should be known with an established degree of certainty.

3.10
stock solution

solution with accurately known analyte concentration(s), prepared from pure chemicals (3.9)

NOTE Stock solutions are reference materials within the meaning of ISO Guide 30.
3.11
test sample

portion taken from the laboratory sample after homogenizing, grinding, dividing, etc.

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ISO 22036:2008(E)
3.12
test sample solution

solution prepared after extraction or dissolution of the test sample according to appropriate specifications

NOTE The test sample solution is intended for use for measurement.
4 Principle

Inductively coupled plasma - atomic emission spectrometry (ICP-AES) can be used to determine trace

elements in solution. The solution is dispersed by a suitable nebulizer and the resulting aerosol is transported

into the plasma torch. In a radio-frequency inductively coupled plasma the solvent is evaporated, the dried

salts are then vaporized, dissociated, atomized and ionized. The atoms or ions are excited thermally and the

number of photons emitted during transition to a lower energy level are measured with optical emission

spectrometry. The spectra are dispersed by a grating spectrometer, and the intensities of the emission lines

are monitored by photosensitive devices. The identification of the element takes place by means of the

wavelength of the radiation (energy of photons), while the concentration of the element is proportional to the

intensity of the radiation (number of photons). The ICP-AES method can be used to perform multi-element

determinations using sequential or simultaneous optical systems and axial or radial viewing of the plasma.

Table 1 shows examples of recommended wavelengths, and detection limits for one particular instrument.

Data given are valid for water acidified with nitric acid with an optimized instrument. Using other instruments

can lead to different detection limits. Adoption of other wavelengths is possible.

Table 1 — Recommended wavelengths and estimated detection limits for selected elements and

[9]

wavelengths obtained using ICP-AES Varian, Vista-MPX megapixel (CD detector features)

Element wavelengths and analytical lines Axial viewing Radial viewing

Element Wavelength Lines Detection limit Detection limit Detection limit Detection limit

a b a b
nm I = atom µg/l mg/kg µg/l mg/kg
II = ion
Aluminium 396,068 1 0,10 4 0,4
308,215 I 2,6 0,26
309,271 I
396,152 I 0,1 0,01 4 0,4
167,078 l 0,3 0,03 1 0,1
Antimony 206,833 I 0,5 0,5 16 1,6
217,581 I 1,8 0,18 5 0,5
231,146 l 2 0,2
Arsenic 188,979 2 0,2 12 1,2
193,696 1 0,1 11 1,1
197,198 I 5 0,5
189,042 l
188,979 l 1,5 0,15 5 0,5
Barium 233,527 II 0,06 0,006 0,7 0,07
455,403 II 0,01 0,001 0,15 0,02
493,409 II 0,04 0,004 0,15 0,02
Beryllium 313,107 II 0,03 0,003 0,15 0,02
313,402 II 0,01 0,001 0,15 0,02
234,861 II 0,01 0,001 0,05 0,005
Bismuth 223,061 I 1,8 0,18 6 0,6
306,771 l 17 1,7
315,887
Boron 208,959 I 0,7 0,07 1,2 0,12
249,678 I 1,1 0,11 1,5 0,15
249,772 l 0,5 0,05 1 0,1
© ISO 2008 – All rights reserved 3
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SIST ISO 22036:2019
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Table 1 (continued)
Element wavelengths and analytical lines Axial viewing Radial viewing

Element Wavelength Lines Detection limit Detection limit Detection limit Detection limit

a b a b
nm I = atom µg/l mg/kg µg/l mg/kg
II = ion
Cadmium 214,438 II 0,1 0,01 0,5 0,05
226,502 II 0,11 0,011 0,6 0,06
228,802 II 0,20 0,02 0,5 0,05
Calcium 396,847 II 0,5 0,05 0,3 0,03
317,933 II 0,3 0,03 6,5 0,7
393,366 II 0,5 0,05
Chromium 267,716 II 0,1 0,01 1 0,1
205,552 II 0,3 0,03
206,149 II
283,563 II 0,2 0,02
284,325 II
Cobalt 238,892 II 0,4 0,04 1,2 0,1
0,4 0,04 1 0,1
228,616 II
230,786 II
Copper 327,396 I 0,3 0,03 1,5 0,1
224,700 II
324,754 I 0,6 0,06
Iron 238,204 II 0,3 0,03 0,9 0,09
239,562 II
259,940 II 0,5 0,05 0,7 0,07
Lead 220,353 II 0,4 0,04 8 0,8
216,999 I
224,688 I
261,418 I
283,306 I 1,8 0,18
Lithium 670,783 I 1,7 0,17 1 0,1
460,286 I 67 6,7
Magnesium 279,553 II 0,02 0,002 0,1 0,01
279,079 II 1 0,1 4 0,4
285,213 I 0,06 0,006 0,25 0,025
279,806 II 1,5 0,15 10 1
Manganese 257,610 II 0,10 0,01 0,13 0,01
260,569 II
279,482 II
293,306 II 0,4 0,04 1 0,1
403,076 I 0,8 0,08
259,372 ll 0,05 0,005
Mercury 194,227 II 1,2 0,12 2,5 0,25
1 0,1 2 0,20
253,652 I
184,890 I
Molybdenum 202,030 II 0,2 0,02 2 0,2
204,598 II 0,6 0,06 3 0,3
Nickel 231,604 II 0,4 0,04 2,1 0,2
221,647 II 0,3 0,03 1,4 0,14
216,555 I 0,15 0,015
232,003 ll
Phosphorus 177,428 I 1,5 0,15 25 2,5
178,222 I 7 0,7
213,618 I 1,3 0,13 5,3 0,53
214,914 l 1 0,1 11 1,1
4 © ISO 2008 – All rights reserved
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Table 1 (continued)
Element wavelengths and analytical lines Axial viewing Radial viewing

Element Wavelength Lines Detection limit Detection limit Detection limit Detection limit

a b a b
nm I = atom µg/l mg/kg µg/l mg/kg
II = ion
Potassium 766,491 I 0,2 0,02 4 0,4
769,896 I 23 2,3 12 1,2
Rubidium 780,03 I 1 0,1 5 0,5
Selenium 196,026 I 0,8 0,08 16 1,6
203,985 I 2,8 0,28
Silicon 251,611 I 0,9 0,09 2,2 0,22
212,412 I 1,3 0,13 5 0,5
288,158 I 1 0,1
Silver 328,068 I 0,4 0,04 1 0,1
338,289 I 1 0,1 2 0,2
Sodium 589,592 I 0,6 0,06 1,5 0,2
588,995 I 12 1,2 15 0,15
330,237 I 69 6,9
Strontium 407,771 II 0,01 0,001 0,1 0,01
421,552 II 0,01 0,001 0,1 0,01
460,733 I 0,3 0,03
Sulfur 181,962 I 4 0,4 13 1,3
182,036
Thallium 190,800 II 2 0,2 13 0,1
190,864 II
Tin 189,933 II 6 0,6 8 0,8
235,484 I 23 2,3 20 2,0
283,998 l 11
Titanium 336,121 II 0,15 0,015 1 0,1
334,941 II 0,2 0,02 0,25 0,25
337,280 II 0,2 0,02 1 0,1
Vanadium 292,402 II 0,3 0,03 2 0,2
309,310 II 0,08 0,008
311,837 II 0,1 0,01
290,882 ll
310,230 ll
Zinc 213,856 I 0,05 0,005 0,8 0,08
202,548 II 0,03 0,003 0,7 0,07
206,200 ll 0,15 0,015 2 0,02
Typical 3-sigma detection limits using 30 s integration time.

The detection limit (LOD), as a mass fraction of the soil sample in mg/kg dry matter, is given assuming that a test sample of 1 g is

extracted and diluted to 100 ml. The LOD shown in Table 1 are only examples of a given equipment and laboratory conditions. Each

laboratory shall select appropriate wavelengths and determine LOD under its specific laboratory conditions.

NOTE The wavelengths given in Table 1 are often used, but they are given here only as an example. Adoption of

other wavelengths is possible. The limit of detection and the linear range vary for each element with the wavelength,

spectrometer, operating conditions and matrix load in the sample solution. If solutions with high salt concentrations (typical

for soil extract solutions) are measured, the LOD is substantially increased compared with water samples.

© ISO 2008 – All rights reserved 5
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SIST ISO 22036:2019
ISO 22036:2008(E)

This International Standard refers specifically to the use of inductively coupled plasma - atomic emission

spectrometry. Users of this International Standard are advised to operate their laboratories to accepted quality

control procedures. Certified Reference Materials (CRM) should be used to establish the amounts of the

relevant elements in in-house reference materials. The latter can be used for routine quality control of the

procedures given in this International Standard.

Results shall be established with control charts, for each element, within the laboratory. No result shall be

accepted which falls outside an agreed limit. Quality control procedures based on widely accepted statistical

techniques shall be used to establish such limits, that these are stable and that no long-term drift is occurring.

Certified Reference Materials should be used regularly to maintain the integrity of the in-house reference

materials and, thereby, the quality control system.
5 Interferences
5.1 General

The presence of different matrix elements in the sample solution can cause severe interferences, which result

in systematic errors of the analyte signal. Special techniques, e.g. background correction, matrix matching of

the calibration solution or the standard addition technique, can be used to compensate such interferences.

Interferences are classified into spectral and non-spectral interferences. They can be specific for an analyte or

non-specific.

Spectral interferences (see 5.2) are due to incomplete isolation of the radiation emitted by the analyte from

other radiation sources detected and amplified by the detection system (additive interferences).

Non-spectral interferences (see 5.3) are interferences where the sensitivity changes due to the composition of

the solutions to be measured (multiplicative interferences). The observed matrix effect is a composite

interference due to all of the components in the sample solution.

Background correction is required for trace element determination. Background emission shall be measured

adjacent to analyte lines on samples during analysis. The position selected for the background-intensity

measurement, on one or both sides of the analytical line, is determined by the complexity of the spectrum

adjacent to the analyte line. The position used should be as free as possible from spectral interference, and

should reflect the same change in background intensity as occurs at the analyte wavelength measured.

Increase in background is more intensive with axial-view instruments. Background correction is not required in

cases of line broadening, where the analytical result is actually degraded by a background correction

measurement.
5.2 Spectral interferences
Spectral interferences are, e.g.

⎯ partially or complete overlap of an emission line of another element with that of the analyte; special case:

increase of background caused by a wing of a strong emission line located nearby, e.g. sloping

background shift at Pb 220,353 nm caused by Al 220,463 nm,

⎯ overlap of a molecular band from a multi-atomic particle formed in the plasma from the solvent, the

ambient air or the gases (e.g. N , NO, NH, OH, CN) with the emission line of an analyte,

⎯ background increase caused by recombination phenomena, e.g. continuum emitted by Al between

190 nm to 220 nm,
⎯ increase of background caused by stray light.
6 © ISO 2008 – All rights reserved
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SIST ISO 22036:2019
ISO 22036:2008(E)

A spectral line overlap usually leads to the choice of an alternative line. If this is not possible, mathematical

correction procedures (e.g. inter-element correction technique, multi-component spectral fitting) can be used

to compensate the interference. A parallel background shift can be compensated by background correction.

To correct a sloping background shift, two background correction points on each side of the peak are used.

For the investigation of spectral interferences of aqua regia extracts of soil, the most prominent lines of the

analytes As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Tl and Zn were used. The most important soil elements Al, As, Ca,

Cr, Cu, Co, Cu, Fe, Mg, Mn, Mo, Ni, Ti, V and Zn were used as interference elements in two concentrations:

100 mg/l and 500 mg/l. These element concentrations are equal to 0,33 % and 1,67 % (mass fraction) in soils,

for aqua regia extraction carried out in accordance with ISO 11466.

Tables B.1 and B.3 in Annex B give a summary of potential spectral interferences when analysing aqua regia

extracts of soils. Both the interfering elements and the emission line of these elements are given. A Perkin-

Elmer Optima 3000 instrument with a spectral resolution of 0,006 nm at 200 nm was employed for the study

for Table B.1, and a Varian Vista-PRO with axial plasma for Table B.3. Line coincidences, which are

dependent on the spectral resolution of the spectrometer, only become perceptible when the concentration of

the interfering element and analyte reach a critical level.

In Table B.2 the interference is expressed as analyte concentration equivalents (i.e. false positive increase of

analyte concentrations) arising from 100 mg/l and 500 mg/l of the interfering element, respectively. The data

are intended as a guide for indicating the extent of potential interference. The user should be aware that other

instruments may exhibit somewhat different levels of interference than those shown in Table B.2, because the

intensities vary with instrument construction and operating conditions, such as power, introduction gas flow

rate, and observation height.

Some potential spectral interferences observed for the recommended wavelengths using an axial viewing

instrument are given in Table B.3. For example, if Cr is to be determined at 267,716 nm in a sample

containing approximately 100 mg/l of Al, a false positive signal is observed for a Cr level equivalent to

approximately 0,06 mg/l. The user should take into account that other instruments may exhibit levels of

interference somewhat different from those shown in Table B.3. The interference effects shall be evaluated for

each individual instrument, whether configured as a sequential or simultaneous instrument. For each

instrument, intensities vary not only with optical resolution but also with operating conditions (such as power,

viewing height and argon flow rate). When using the recommended wavelengths, the analyst is required to

determine and document for each wavelength the effect from referenced interferences (see Table B.3) as well

as any other suspected interferences that may be specific to the instrument or matrix. The analyst should use

a computer routine for automatic correction on all analysis.
5.3 Non-spectral interferences

Non-spectral interferences can occur during nebulization or sample introduction (physical nature) or in the

plasma itself (both physical and chemical natures).

Transport interferences are due to differences in the physical properties (viscosity, surface tension, density)

between the sample solutions and the calibration solutions. They are caused by differences in the dissolved

solid content (e.g. salts, organic substances) as well as in the type or concentration of acid. As a consequence,

the supply of solution to the nebulizer, the efficiency of nebulization and the droplet size distribution of the

aerosol are altered, and hence the sensitivity changes. Errors due to these interferences can be overcome by

dilution of the solutions, by matrix matching, by standard addition or by the reference element technique

(internal standardization).

1) Perkin-Elmer Optima 3000 and Varian Vista-Pro are examples of suitable products available commercially. This

information is given for the convenience of users of this document and does not constitute an endorsement by ISO of

these products.
© ISO 2008 – All rights reserved 7
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SIST ISO 22036:2019
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Excitation interferences cause changes in the sensitivity as a result of changed plasma conditions due to

introduction of the matrix. These changes are attributed to a change in the excitation conditions in the plasma

caused by easily ionizable elements like alkali metals. Enhancement or depressant effect of easily ionizable

elements on analyte emission depends on the operating conditions of the plasma (e.g. power, sample

introduction gas flow rate, observation height), and differ from element to element. Improvement of the plasma

conditions can therefore reduce excitation interferences. Other possibilities are dilution of the solutions, matrix

matching or the standard addition technique.
6 Reagents
All reagents shall be of recognized analytical grade.
6.1 Water.

Use demineralized water or water distilled from an all-glass apparatus, conforming to Grade 2 of ISO 3696.

The water used for blank determinations, and for preparing reagents and standard solutions, shall have

element concentrations that are negligible compared with the lowest concentration to be determined in the

sample solutions.

An example of reagents used for aqua regia extractions in accordance with ISO 11466 is given in the following.

Reagents based on other International Standards or other documents should be prepared accordingly.

6.2 Nitric acid, w(HNO ) = 65 %; ~ 1,40 g/ml.
The same batch of nitric acid shall be used throughout the procedure.
6.3 Nitric acid (1+1).
Add 500 ml nitric acid (6.2) to 400 ml water, mix and dilute to 1 l.
6.4 Hydrochloric acid, w(HCl) = 37 %; ~ 1,18 g/ml.
The same batch of hydrochloric acid shall be used throughout the procedure.
6.5 Hydrochloric acid (1+1).
Add 500 ml hydrochloric acid (6.4) to 400 ml water (6.1), mix and dilute to 1 l.

Other reagents used for dissolution or extraction of soil samples are described in the relevant standa

...

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.NRQualité du sol - Dosage des éléments traces dans des extraits de sol par spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES)Soil quality - Determination of trace elements in extracts of soil by inductively coupled plasma - atomic emission spectrometry (ICP - AES)71.040.50Fizikalnokemijske analitske metodePhysicochemical methods of analysis13.080.10Chemical characteristics of soilsICS:Ta slovenski standard je istoveten z:ISO 22036:2008oSIST ISO 22036:2019en01-maj-2019oSIST ISO 22036:2019SLOVENSKI

STANDARD
oSIST ISO 22036:2019
Reference numberISO 22036:2008(E)© ISO 2008

INTERNATIONAL STANDARD ISO22036First edition2008-12-15Soil quality — Determination of trace elements in extracts of soil by inductively coupled plasma - atomic emission spectrometry (ICP-AES) Qualité du sol — Dosage des éléments traces dans des extraits de sol par spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES)

oSIST ISO 22036:2019

ISO 22036:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

COPYRIGHT PROTECTED DOCUMENT

ISO 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 • CH-1211 Geneva 20 Tel.

+ 41 22 749 01 11 Fax
+ 41 22 749 09 47 E-mail
copyright@iso.org Web
www.iso.org Published in Switzerland
ii © ISO 2008 – All rights reserved
oSIST ISO 22036:2019

ISO 22036:2008(E) © ISO 2008 – All rights reserved iii Contents Page Foreword............................................................................................................................................................iv 1 Scope......................................................................................................................................................1 2 Normative references............................................................................................................................1 3 Terms and definitions...........................................................................................................................2 4 Principle..................................................................................................................................................3 5 Interferences..........................................................................................................................................6 5.1 General...................................................................................................................................................6 5.2 Spectral interferences...........................................................................................................................6 5.3 Non-spectral interferences...................................................................................................................7 6 Reagents.................................................................................................................................................8 7 Instrumentation.....................................................................................................................................9 8 Procedure.............................................................................................................................................10 8.1 Cleaning of glassware.........................................................................................................................10 8.2 Instrument performance parameters.................................................................................................10 8.3 Instrument optimization......................................................................................................................11 8.4 Alignment of the spectrometer..........................................................................................................11 8.5 Calibration methods............................................................................................................................12 8.6 Solutions to be prepared....................................................................................................................12 8.7 Measurement procedure.....................................................................................................................13 9 Calculation of results..........................................................................................................................14 10 Precision...............................................................................................................................................14 11 Expression of results..........................................................................................................................14 12 Test report............................................................................................................................................15 Annex A (informative)

Repeatability and precision results..........................................................................16 Annex B (informative)

Interferences...............................................................................................................19 Bibliography......................................................................................................................................................30

oSIST ISO 22036:2019

ISO 22036:2008(E) iv © ISO 2008 – All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 22036 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics.

oSIST ISO 22036:2019

INTERNATIONAL STANDARD ISO 22036:2008(E) © ISO 2008 – All rights reserved 1 Soil quality — Determination of trace elements in extracts of soil by inductively coupled plasma - atomic emission spectrometry (ICP-AES) WARNING — The procedures in this International Standard should be carried out by competent, trained persons. Some of the techniques and reagents, including the use of equipment, are potentially very dangerous. Users of this International Standard who are not thoroughly familiar with the potential dangers and related safe practices should take professional advice before commencing any operation. 1 Scope This International Standard describes the determination of trace elements in digests or extraction solutions from soil by inductively coupled plasma - atomic emission spectrometry (ICP-AES) for 34 elements (see Table 1). This multi-element determination method is applicable to soil extracts obtained with aqua regia in accordance with ISO 11466, with DTPA in accordance with ISO 14870 or other weak extractants, or soil extracts for the determination of total element contents using the acid digestion method of ISO 14869-1 or the fusion method of ISO 14869-2. The choice of calibration method depends on the extractant and can be adapted to the extractant concentration. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO Guide 32, Calibration in analytical chemistry and use of certified reference materials ISO 3696, Water for analytical laboratory use — Specification and test methods ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results — Part 1: General principles and definitions ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method ISO 11465, Soil quality — Determination of dry matter and water content on a mass basis — Gravimetric method ISO 11466, Soil quality — Extraction of trace elements soluble in aqua regia ISO 14869-1, Soil quality — Dissolution for the determination of total element content — Part 1: Dissolution with hydrofluoric and perchloric acids ISO 14869-2, Soil quality — Dissolution for the determination of total element content — Part 2: Dissolution by alkaline fusion ISO 14870, Soil quality — Extraction of trace elements by buffered DTPA solution oSIST ISO 22036:2019

ISO 22036:2008(E) 2 © ISO 2008 – All rights reserved 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 5725-1, ISO 5725-2, ISO Guide 32 and the following apply. 3.1 analyte element to be determined 3.2 blank calibration solution solution prepared in the same way as the calibration solution but leaving out the analytes 3.3 blank test solution solution prepared in the same way as the test sample solution but omitting the test portion 3.4 calibration solution solution used to calibrate the instrument, prepared from stock solutions by adding acids, buffer, reference element and salts as needed 3.5 instrument detection limit lowest concentration that can be detected with a defined statistical probability using a clean instrument and a clean solution NOTE The clean solution is usually dilute nitric acid. 3.6 laboratory sample sample sent to the laboratory for analysis 3.7 linearity straight-line relationship between the mean result of measurement and the quantity (concentration) of the analyte 3.8 method detection limit lowest concentration that can be detected using a specific analytical method with a defined statistical probability for defined maximum matrix element concentrations 3.9 pure chemical chemical with the highest available purity and known stoichiometry NOTE The content of analyte and contaminants should be known with an established degree of certainty. 3.10 stock solution solution with accurately known analyte concentration(s), prepared from pure chemicals (3.9) NOTE Stock solutions are reference materials within the meaning of ISO Guide 30. 3.11 test sample portion taken from the laboratory sample after homogenizing, grinding, dividing, etc. oSIST ISO 22036:2019

ISO 22036:2008(E) © ISO 2008 – All rights reserved 3 3.12 test sample solution solution prepared after extraction or dissolution of the test sample according to appropriate specifications NOTE The test sample solution is intended for use for measurement. 4 Principle Inductively coupled plasma - atomic emission spectrometry (ICP-AES) can be used to determine trace elements in solution. The solution is dispersed by a suitable nebulizer and the resulting aerosol is transported into the plasma torch. In a radio-frequency inductively coupled plasma the solvent is evaporated, the dried salts are then vaporized, dissociated, atomized and ionized. The atoms or ions are excited thermally and the number of photons emitted during transition to a lower energy level are measured with optical emission spectrometry. The spectra are dispersed by a grating spectrometer, and the intensities of the emission lines are monitored by photosensitive devices. The identification of the element takes place by means of the wavelength of the radiation (energy of photons), while the concentration of the element is proportional to the intensity of the radiation (number of photons). The ICP-AES method can be used to perform multi-element determinations using sequential or simultaneous optical systems and axial or radial viewing of the plasma. Table 1 shows examples of recommended wavelengths, and detection limits for one particular instrument. Data given are valid for water acidified with nitric acid with an optimized instrument. Using other instruments can lead to different detection limits. Adoption of other wavelengths is possible. Table 1 — Recommended wavelengths and estimated detection limits for selected elements and wavelengths obtained using ICP-AES Varian, Vista-MPX megapixel (CD detector features) [9] Element wavelengths and analytical lines Axial viewing Radial viewing Element Wavelength nm Lines I = atom

II = ion Detection limitµg/l a Detection limitmg/kg b Detection limit µg/l a Detection limitmg/kg b Aluminium 396,068 308,215 309,271 396,152 167,078

I I I l 1 2,6
0,1 0,3 0,10 0,26
0,01 0,03 4
4 1 0,4

0,4 0,1 Antimony 206,833 217,581 231,146 I I l 0,5 1,8 2 0,5 0,18 0,2 16 5 1,6 0,5 Arsenic 188,979 193,696 197,198 189,042 188,979

I l l 2 1 5
1,5 0,2 0,1 0,5
0,15 12 11
5 1,2 1,1

0,5 Barium 233,527 455,403 493,409 II II II 0,06 0,01 0,04 0,006 0,001 0,004 0,7 0,15 0,15 0,07 0,02 0,02 Beryllium 313,107 313,402 234,861 II II II 0,03 0,01 0,01 0,003 0,001 0,001 0,15 0,15 0,05 0,02 0,02 0,005 Bismuth 223,061 306,771 315,887 I l 1,8 17 0,18 1,7 6 0,6 Boron 208,959 249,678 249,772 I I l 0,7 1,1 0,5 0,07 0,11 0,05 1,2 1,5 1 0,12 0,15 0,1 oSIST ISO 22036:2019

ISO 22036:2008(E) 4 © ISO 2008 – All rights reserved Table 1 (continued) Element wavelengths and analytical lines Axial viewing Radial viewing Element Wavelength nm Lines I = atom

II = ion Detection limitµg/l a Detection limitmg/kg b Detection limit µg/l a Detection limitmg/kg b Cadmium 214,438 226,502 228,802 II II II 0,1 0,11 0,20 0,01 0,011 0,02 0,5 0,6 0,5 0,05 0,06 0,05 Calcium 396,847 317,933 393,366 II II II 0,5 0,3 0,5 0,05 0,03 0,05 0,3 6,5 0,03 0,7 Chromium 267,716 205,552 206,149 283,563 284,325 II II II II II 0,1 0,3

0,2 0,01 0,03

0,02 1 0,1 Cobalt 238,892 228,616 230,786 II II II 0,4 0,4 0,04 0,04 1,2 1 0,1 0,1 Copper 327,396 224,700 324,754 I II I 0,3

0,6 0,03
0,06 1,5 0,1 Iron 238,204 239,562 259,940 II II II 0,3
0,5 0,03
0,05 0,9
0,7 0,09
0,07 Lead 220,353 216,999 224,688 261,418 283,306 II I I I I 0,4
1,8 0,04

0,18 8 0,8 Lithium 670,783 460,286 I I 1,7 67 0,17 6,7 1 0,1 Magnesium 279,553 279,079 285,213 279,806 II II I II 0,02 1 0,06 1,5 0,002 0,1 0,006 0,15 0,1 4 0,25 10 0,01 0,4 0,025 1 Manganese 257,610 260,569 279,482 293,306 403,076 259,372 II II II II I ll 0,10

0,4 0,8 0,05 0,01
0,04 0,08 0,005 0,13
1 0,01

0,1 Mercury 194,227 253,652 184,890 II I I 1,2 1 0,12 0,1 2,5 2 0,25 0,20 Molybdenum 202,030 204,598 II II 0,2 0,6 0,02 0,06 2 3 0,2 0,3 Nickel 231,604 221,647 216,555 232,003 II II I ll 0,4 0,3 0,15 0,04 0,03 0,015 2,1 1,4 0,2 0,14 Phosphorus 177,428 178,222 213,618 214,914 I I I l 1,5 7 1,3 1 0,15 0,7 0,13 0,1 25

5,3 11 2,5
0,53 1,1 oSIST ISO 22036:2019

ISO 22036:2008(E) © ISO 2008 – All rights reserved 5 Table 1 (continued) Element wavelengths and analytical lines Axial viewing Radial viewing Element Wavelength nm Lines I = atom

II = ion Detection limitµg/l a Detection limitmg/kg b Detection limit µg/l a Detection limitmg/kg b Potassium 766,491 769,896 I I 0,2 23 0,02 2,3 4 12 0,4 1,2 Rubidium 780,03 I 1 0,1 5 0,5 Selenium 196,026 203,985 I I 0,8 2,8 0,08 0,28 16 1,6 Silicon 251,611 212,412 288,158 I I I 0,9 1,3 1 0,09 0,13 0,1 2,2 5 0,22 0,5 Silver 328,068 338,289 I I 0,4 1 0,04 0,1 1 2 0,1 0,2 Sodium 589,592 588,995 330,237 I I I 0,6 12 69 0,06 1,2 6,9 1,5 15 0,2 0,15 Strontium 407,771 421,552 460,733 II II I 0,01 0,01 0,3 0,001 0,001 0,03 0,1 0,1 0,01 0,01 Sulfur 181,962 182,036 I 4 0,4 13 1,3 Thallium 190,800 190,864 II II 2 0,2 13 0,1 Tin 189,933 235,484 283,998 II I l 6 23 11 0,6 2,3 8 20 0,8 2,0 Titanium 336,121 334,941 337,280 II II II 0,15 0,2 0,2 0,015 0,02 0,02 1 0,25 1 0,1 0,25 0,1 Vanadium 292,402 309,310 311,837 290,882 310,230 II II II ll ll 0,3 0,08 0,1 0,03 0,008 0,01 2 0,2 Zinc 213,856 202,548 206,200 I II ll 0,05 0,03 0,15 0,005 0,003 0,015 0,8 0,7 2 0,08 0,07 0,02 a Typical 3-sigma detection limits using 30 s integration time. b The detection limit (LOD), as a mass fraction of the soil sample in mg/kg dry matter, is given assuming that a test sample of 1 g is extracted and diluted to 100 ml. The LOD shown in Table 1 are only examples of a given equipment and laboratory conditions. Each laboratory shall select appropriate wavelengths and determine LOD under its specific laboratory conditions. NOTE The wavelengths given in Table 1 are often used, but they are given here only as an example. Adoption of other wavelengths is possible. The limit of detection and the linear range vary for each element with the wavelength, spectrometer, operating conditions and matrix load in the sample solution. If solutions with high salt concentrations (typical for soil extract solutions) are measured, the LOD is substantially increased compared with water samples. oSIST ISO 22036:2019

ISO 22036:2008(E) 6 © ISO 2008 – All rights reserved This International Standard refers specifically to the use of inductively coupled plasma - atomic emission spectrometry. Users of this International Standard are advised to operate their laboratories to accepted quality control procedures. Certified Reference Materials (CRM) should be used to establish the amounts of the relevant elements in in-house reference materials. The latter can be used for routine quality control of the procedures given in this International Standard. Results shall be established with control charts, for each element, within the laboratory. No result shall be accepted which falls outside an agreed limit. Quality control procedures based on widely accepted statistical techniques shall be used to establish such limits, that these are stable and that no long-term drift is occurring. Certified Reference Materials should be used regularly to maintain the integrity of the in-house reference materials and, thereby, the quality control system. 5 Interferences 5.1 General The presence of different matrix elements in the sample solution can cause severe interferences, which result in systematic errors of the analyte signal. Special techniques, e.g. background correction, matrix matching of the calibration solution or the standard addition technique, can be used to compensate such interferences. Interferences are classified into spectral and non-spectral interferences. They can be specific for an analyte or non-specific. Spectral interferences (see 5.2) are due to incomplete isolation of the radiation emitted by the analyte from other radiation sources detected and amplified by the detection system (additive interferences). Non-spectral interferences (see 5.3) are interferences where the sensitivity changes due to the composition of the solutions to be measured (multiplicative interferences). The observed matrix effect is a composite interference due to all of the components in the sample solution. Background correction is required for trace element determination. Background emission shall be measured adjacent to analyte lines on samples during analysis. The position selected for the background-intensity measurement, on one or both sides of the analytical line, is determined by the complexity of the spectrum adjacent to the analyte line. The position used should be as free as possible from spectral interference, and should reflect the same change in background intensity as occurs at the analyte wavelength measured. Increase in background is more intensive with axial-view instruments. Background correction is not required in cases of line broadening, where the analytical result is actually degraded by a background correction measurement. 5.2 Spectral interferences Spectral interferences are, e.g. ⎯ partially or complete overlap of an emission line of another element with that of the analyte; special case: increase of background caused by a wing of a strong emission line located nearby, e.g. sloping background shift at Pb 220,353 nm caused by Al 220,463 nm, ⎯ overlap of a molecular band from a multi-atomic particle formed in the plasma from the solvent, the ambient air or the gases (e.g. N2+, NO, NH, OH, CN) with the emission line of an analyte, ⎯ background increase caused by recombination phenomena, e.g. continuum emitted by Al between 190 nm to 220 nm, ⎯ increase of background caused by stray light. oSIST ISO 22036:2019

ISO 22036:2008(E) © ISO 2008 – All rights reserved 7 A spectral line overlap usually leads to the choice of an alternative line. If this is not possible, mathematical correction procedures (e.g. inter-element correction technique, multi-component spectral fitting) can be used to compensate the interference. A parallel background shift can be compensated by background correction. To correct a sloping background shift, two background correction points on each side of the peak are used. For the investigation of spectral interferences of aqua regia extracts of soil, the most prominent lines of the analytes As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Tl and Zn were used. The most important soil elements Al, As, Ca, Cr, Cu, Co, Cu, Fe, Mg, Mn, Mo, Ni, Ti, V and Zn were used as interference elements in two concentrations: 100 mg/l and 500 mg/l. These element concentrations are equal to 0,33 % and 1,67 % (mass fraction) in soils, for aqua regia extraction carried out in accordance with ISO 11466. Tables B.1 and B.3 in Annex B give a summary of potential spectral interferences when analysing aqua regia extracts of soils. Both the interfering elements and the emission line of these elements are given. A Perkin-Elmer Optima 30001) instrument with a spectral resolution of 0,006 nm at 200 nm was employed for the study for Table B.1, and a Varian Vista-PRO1) with axial plasma for Table B.3. Line coincidences, which are dependent on the spectral resolution of the spectrometer, only become perceptible when the concentration of the interfering element and analyte reach a critical level. In Table B.2 the interference is expressed as analyte concentration equivalents (i.e. false positive increase of analyte concentrations) arising from 100 mg/l and 500 mg/l of the interfering element, respectively. The data are intended as a guide for indicating the extent of potential interference. The user should be aware that other instruments may exhibit somewhat different levels of interference than those shown in Table B.2, because the intensities vary with instrument construction and operating conditions, such as power, introduction gas flow rate, and observation height. Some potential spectral interferences observed for the recommended wavelengths using an axial viewing instrument are given in Table B.3. For example, if Cr is to be determined at 267,716 nm in a sample containing approximately 100 mg/l of Al, a false positive signal is observed for a Cr level equivalent to approximately 0,06 mg/l. The user should take into account that other instruments may exhibit levels of interference somewhat different from those shown in Table B.3. The interference effects shall be evaluated for each individual instrument, whether configured as a sequential or simultaneous instrument. For each instrument, intensities vary not only with optical resolution but also with operating conditions (such as power, viewing height and argon flow rate). When using the recommended wavelengths, the analyst is required to determine and document for each wavelength the effect from referenced interferences (see Table B.3) as well as any other suspected interferences that may be specific to the instrument or matrix. The analyst should use a computer routine for automatic correction on all analysis. 5.3 Non-spectral interferences Non-spectral interferences can occur during nebulization or sample introduction (physical nature) or in the plasma itself (both physical and chemical natures). Transport interferences are due to differences in the physical properties (viscosity, surface tension, density) between the sample solutions and the calibration solutions. They are caused by differences in the dissolved solid content (e.g. salts, organic substances) as well as in the type or concentration of acid. As a consequence, the supply of solution to the nebulizer, the efficiency of nebulization and the droplet size distribution of the aerosol are altered, and hence the sensitivity changes. Errors due to these interferences can be overcome by dilution of the solutions, by matrix matching, by standard addition or by the reference element technique (internal standardization).

1) Perkin-Elmer Optima 3000 and Varian Vista-Pro are examples of suitable products available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of these products. oSIST ISO 22036:2019

ISO 22036:2008(E) 8 © ISO 2008 – All rights reserved Excitation interferences cause changes in the sensitivity as a result of changed plasma conditions due to introduction of the matrix. These changes are attributed to a change in the excitation conditions in the plasma caused by easily ionizable elements like alkali metals. Enhancement or depressant effect of easily ionizable elements on analyte emission depends on the operating conditions of the plasma (e.g. power, sample introduction gas flow rate, observation height), and differ from element to element. Improvement of the plasma conditions can therefore reduce excitation interferences. Other possibilities are dilution of the solutions, matrix matching or the standard addition technique. 6 Reagents All reagents shall be of recognized analytical grade. 6.1 Water. Use demineralized water or water distilled from an all-glass apparatus, conforming to Grade 2 of ISO 3696. The water used for blank determinations, and for preparing reagents and standard solutions, shall have element concentrations that are negligible compared with the lowest concentration to be determined in the sample solutions. An example of reagents used for aqua regia extractions in accordance with ISO 11466 is given in the following. Reagents based on other International Standards or other documents should be prepared accordingly. 6.2 Nitric acid, w(HNO3) = 65 %; ~ 1,40 g/ml. The same batch of nitric acid shall be used throughout the procedure. 6.3 Nitric acid (1+1). Add 500 ml nitric acid (6.2) to 400 ml water, mix and dilute to 1 l. 6.4 Hydrochloric acid, w(HCl) = 37 %; ~ 1,18 g/ml. The same batch of hydrochloric acid shall be used throughout the procedure. 6.5 Hydrochloric acid (1+1). Add 500 ml hydrochloric acid (6.4) to 400 ml water (6.1), mix and dilute to 1 l. Other reagents used for dissolution or extraction of soil samples are described in the relevant standards. 6.6 Preparation of stock solutions and standard solutions of individual elements. Two sources of stock solutions are available: ⎯ commercially available stock solutions; ⎯ stock solutions prepared in the laboratory from pure elements or stoichiometrically defined salts or oxides. The concentrations of single-element solutions are 1 000 mg/l. NOTE Commercially available stock solutions have the advantage that they remove the need to handle directly toxic metals, especially thallium. However, special care needs to be taken that these solutions are supplied with a certified composition from a reputable source and are checked on a regular basis. 6.7 Intermediate standard solutions. Intermediate standard solutions may be prepared for each individual analyte, or for multi-element standard solutions by dilution of stock solutions. These solutions should be stabilized by adding 10 ml nitric acid (6.3) to 100 ml of solution. The intermediate solutions have only limited stability and should be discarded after three months, depending on the solution concentration. oSIST ISO 22036:2019

ISO 22036:2008(E) © ISO 2008 – All rights reserved 9 6.8 Multi-element standard solutions. If several elements are to be determined on each sample, it can be more convenient to prepare multi-element standard solutions. Suggested multi-element mixed standard solutions are as follows: ⎯ Mixed standard solution 1: Al, B, Be, Cd, Co, Cr, Cu, Fe, Pb, Li, Mn, Mo, Ni, V

...

NORME ISO
INTERNATIONALE 22036
Première édition
2008-12-15
Qualité du sol — Dosage des éléments
traces dans des extraits de sol par
spectrométrie d'émission atomique
avec plasma induit par haute fréquence
(ICP-AES)
Soil quality — Determination of trace elements in extracts of soil by
inductively coupled plasma - atomic emission spectrometry (ICP-AES)
Numéro de référence
ISO 22036:2008(F)
ISO 2008
---------------------- Page: 1 ----------------------
ISO 22036:2008(F)
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ii © ISO 2008 – Tous droits réservés
---------------------- Page: 2 ----------------------
ISO 22036:2008(F)
Sommaire Page

Avant-propos .....................................................................................................................................................iv

1 Domaine d'application ..........................................................................................................................1

2 Références normatives.........................................................................................................................1

3 Termes et définitions ............................................................................................................................2

4 Principe...................................................................................................................................................3

5 Interférences ..........................................................................................................................................6

5.1 Généralités .............................................................................................................................................6

5.2 Interférences spectrales .......................................................................................................................6

5.3 Interférences non spectrales ...............................................................................................................8

6 Réactifs...................................................................................................................................................8

7 Instrumentation ...................................................................................................................................10

8 Mode opératoire...................................................................................................................................11

8.1 Nettoyage de la verrerie......................................................................................................................11

8.2 Paramètres relatifs aux performances de l'instrument ...................................................................11

8.3 Optimisation des instruments............................................................................................................11

8.4 Alignement du spectromètre..............................................................................................................11

8.5 Méthodes d'étalonnage.......................................................................................................................13

8.6 Solutions à préparer............................................................................................................................13

8.7 Mode opératoire de mesurage ...........................................................................................................14

9 Calcul des résultats.............................................................................................................................15

10 Fidélité ..................................................................................................................................................15

11 Expression des résultats....................................................................................................................15

12 Rapport d'essai....................................................................................................................................16

Annexe A (informative) Répétabilité et fidélité des résultats .......................................................................17

Annexe B (informative) Interférences .............................................................................................................20

Bibliographie.....................................................................................................................................................34

© ISO 2008 – Tous droits réservés iii
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ISO 22036:2008(F)
Avant-propos

L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes nationaux de

normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est en général confiée

aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude a le droit de faire partie du

comité technique créé à cet effet. Les organisations internationales, gouvernementales et non

gouvernementales, en liaison avec l'ISO participent également aux travaux. L'ISO collabore étroitement avec

la Commission électrotechnique internationale (CEI) en ce qui concerne la normalisation électrotechnique.

Les Normes internationales sont rédigées conformément aux règles données dans les Directives ISO/CEI,

Partie 2.

La tâche principale des comités techniques est d'élaborer les Normes internationales. Les projets de Normes

internationales adoptés par les comités techniques sont soumis aux comités membres pour vote. Leur

publication comme Normes internationales requiert l'approbation de 75 % au moins des comités membres

votants.

L'attention est appelée sur le fait que certains des éléments du présent document peuvent faire l'objet de

droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable de ne

pas avoir identifié de tels droits de propriété et averti de leur existence.

L'ISO 22036 a été élaborée par le comité technique ISO/TC 190, Qualité du sol, sous-comité SC 3, Méthodes

chimiques et caractéristiques du sol.
iv © ISO 2008 – Tous droits réservés
---------------------- Page: 4 ----------------------
NORME INTERNATIONALE ISO 22036:2008(F)
Qualité du sol — Dosage des éléments traces dans des extraits
de sol par spectrométrie d'émission atomique avec plasma
induit par haute fréquence (ICP-AES)

AVERTISSEMENT — Il convient que les modes opératoires décrits dans la présente Norme

internationale soient appliqués par des personnes formées et compétentes. Certaines méthodes et

certains réactifs, y compris l'utilisation des équipements, sont potentiellement très dangereux. Il

convient que les utilisateurs de la présente Norme internationale qui ne sont pas suffisamment

informés des dangers potentiels et des pratiques de sécurité associées consultent des professionnels

pour avis avant de commencer toute opération.
1 Domaine d'application

La présente Norme internationale décrit le dosage d'éléments traces dans des solutions de digestion ou des

solutions d'extraction du sol par spectrométrie d'émission atomique avec plasma induit par haute fréquence

(ICP-AES) pour 34 éléments (voir Tableau 1).

Cette méthode de dosage multiéléments est applicable aux extraits de sol obtenus avec de l'eau régale

conformément à l'ISO 11466, avec une solution DTPA conformément à l'ISO 14870, ou avec d'autres agents

d'extraction faibles, ou aux extraits de sols destinés à être utilisés pour le dosage des teneurs élémentaires

totales au moyen de la méthode de digestion par voie acide de l'ISO 14869-1 ou de la méthode par fusion de

l'ISO 14869-2.

Le choix de la méthode d'étalonnage dépend de l'agent d'extraction et peut être adapté à la concentration en

agent d'extraction.
2 Références normatives

Les documents de référence suivants sont indispensables pour l'application du présent document. Pour les

références datées, seule l'édition citée s'applique. Pour les références non datées, la dernière édition du

document de référence s'applique (y compris les éventuels amendements).

ISO Guide 32, Étalonnage en chimie analytique et utilisation de matériaux de référence certifiés

ISO 3696, Eau pour laboratoire à usage analytique — Spécification et méthodes d'essai

ISO 5725-1, Exactitude (justesse et fidélité) des résultats et méthodes de mesure — Partie 1: Principes

généraux et définitions

ISO 5725-2, Exactitude (justesse et fidélité) des résultats et méthodes de mesure — Partie 2: Méthode de

base pour la détermination de la répétabilité et de la reproductibilité d'une méthode de mesure normalisée

ISO 11465, Qualité du sol — Détermination de la teneur pondérale en matière sèche et en eau — Méthode

gravimétrique

ISO 11466, Qualité du sol — Extraction des éléments en traces solubles dans l'eau régale

ISO 14869-1, Qualité du sol — Mise en solution pour la détermination des teneurs élémentaires totales —

Partie 1: Mise en solution par l'acide fluorhydrique et l'acide perchlorique

ISO 14869-2, Qualité du sol — Mise en solution pour la détermination des teneurs élémentaires totales —

Partie 2: Mise en solution par fusion alcaline
© ISO 2008 – Tous droits réservés 1
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ISO 22036:2008(F)

ISO 14870, Qualité du sol — Extraction des éléments en traces par une solution tamponnée de DTPA

3 Termes et définitions

Pour les besoins du présent document, les termes et définitions donnés dans l'ISO 5725-1, l'ISO 5725-2 et le

Guide 32 de l'ISO, ainsi que les suivants, s'appliquent.
3.1
analyte
élément à déterminer
3.2
blanc de solution d'étalonnage

solution préparée de la même manière que la solution d'étalonnage, mais en omettant les analytes

3.3
solution d'essai à blanc

solution préparée de la même manière que la solution d'échantillon pour essai, mais en omettant la prise

d'essai
3.4
solution d'étalonnage

solution utilisée pour étalonner l'instrument, préparée à partir de solutions mères, en y ajoutant des acides,

une solution tampon, un élément de référence et des sels, en fonction des besoins

3.5
limite de détection de l'instrument

concentration la plus faible pouvant être décelée avec une probabilité statistique définie au moyen d'un

instrument propre et d'une solution pure
NOTE La solution pure est généralement de l'acide nitrique dilué.
3.6
échantillon pour laboratoire
échantillon transmis au laboratoire pour analyse
3.7
linéarité

relation directe entre le résultat de mesurage moyen et la quantité (concentration) d'analyte

3.8
limite de détection de la méthode

concentration la plus faible pouvant être décelée au moyen d'une méthode analytique spécifique avec une

probabilité statistique définie pour les concentrations maximales d'éléments matriciels définies

3.9
produit chimique pur

produit chimique de la plus haute pureté disponible et dont la stœchiométrie est connue

NOTE Il convient de connaître la teneur en analyte et en contaminants avec un degré de certitude établi.

3.10
solution mère

solution contenant une ou des concentrations d'analytes connues avec précision, préparée à partir de

produits chimiques purs (3.9)

NOTE Les solutions mères sont des matériaux de référence au sens de la définition donnée dans le Guide 30 de l'ISO.

3.11
échantillon pour essai

prise réalisée à partir de l'échantillon pour laboratoire après homogénéisation, broyage, division, etc.

2 © ISO 2008 – Tous droits réservés
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ISO 22036:2008(F)
3.12
solution d'échantillon pour essai

solution préparée après extraction ou dissolution de l'échantillon pour essai selon des spécifications

appropriées

NOTE La solution d'échantillon pour essai est destinée à être utilisée pour le mesurage.

4 Principe

La spectrométrie d'émission atomique avec plasma induit par haute fréquence (ICP-AES) peut être utilisée

pour doser les éléments traces dans une solution. La solution est dispersée à l'aide d'un nébuliseur approprié,

l'aérosol obtenu étant transporté dans la torche à plasma. Le solvant est évaporé dans un plasma induit par

haute fréquence, les sels formés sont ensuite vaporisés, dissociés, atomisés et ionisés. Les atomes ou les

ions sont soumis à une excitation thermique et le nombre de photons émis au cours de la transition vers un

niveau d'énergie inférieur est mesuré par spectrométrie d'émission optique. Un spectromètre à réseau permet

de disperser les spectres, tandis que des dispositifs photosensibles permettent de contrôler les intensités des

raies d'émission. La longueur d'onde du rayonnement (énergie des photons) permet d'identifier l'élément,

tandis que la concentration de ce dernier est proportionnelle à l'intensité du rayonnement (nombre de

photons). La méthode ICP-AES peut être utilisée pour des dosages multiéléments au moyen de systèmes

optiques séquentiels ou simultanés, avec une observation axiale ou radiale du plasma.

Le Tableau 1 donne des exemples de longueurs d'ondes et de limites de détection recommandées pour un

instrument. Les données fournies sont valables pour de l'eau acidifiée avec de l'acide nitrique mesurée au

moyen d'un instrument optimisé. L'utilisation d'autres instruments peut entraîner des limites de détection

différentes. Il est possible d'utiliser d'autres longueurs d'ondes.

Tableau 1 — Longueurs d'ondes recommandées et limites de détection estimées pour des éléments et

des longueurs d'ondes sélectionnés, obtenus au moyen d'un dispositif ICP-AES Varian, Vista-MPX

[9]
mégapixel (caractéristiques de détecteur CCD)
Longueurs d'ondes et raies d'analyse Observation axiale Observation radiale
de l'élément
Élément Longueur Raies Limite de Limite de Limite de Limite de
d'onde détection détection détection détection
I = atome
a b a b
nm II = ion µg/l mg/kg µg/l mg/kg
Aluminium 396,068 1 0,10 4 0,4
308,215 I 2,6 0,26
309,271 I
396,152 I 0,1 0,01 4 0,4
167,078 l 0,3 0,03 1 0,1
Antimoine 206,833 I 0,5 0,5 16 1,6
217,581 I 1,8 0,18 5 0,5
231,146 l 2 0,2
Arsenic
188,979 2 0,2 12 1,2
193,696 1 0,1 11 1,1
197,198 I 5 0,5
189,042 l
188,979 l 1,5 0,15 5 0,5
Baryum 233,527 II 0,06 0,006 0,7 0,07
455,403 II 0,01 0,001 0,15 0,02
493,409 II 0,04 0,004 0,15 0,02
Béryllium 313,107 II 0,03 0,003 0,15 0,02
313,402 II 0,01 0,001 0,15 0,02
234,861 II 0,01 0,001 0,05 0,005
Bismuth 223,061 I 1,8 0,18 6 0,6
306,771 l 17 1,7
315,887
© ISO 2008 – Tous droits réservés 3
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ISO 22036:2008(F)
Tableau 1 (suite)
Longueurs d'ondes et raies d'analyse Observation axiale Observation radiale
de l'élément
Élément Longueur Raies Limite de Limite de Limite de Limite de
d'onde détection détection détection détection
I = atome
a b a b
nm II = ion µg/l mg/kg µg/l mg/kg
Bore 208,959 I 0,7 0,07 1,2 0,12
249,678 I 1,1 0,11 1,5 0,15
249,772 l 0,5 0,05 1 0,1
Cadmium 214,438 II 0,1 0,01 0,5 0,05
226,502 II 0,11 0,011 0,6 0,06
228,802 II 0,20 0,02 0,5 0,05
Calcium 396,847 II 0,5 0,05 0,3 0,03
317,933 II 0,3 0,03 6,5 0,7
393,366 II 0,5 0,05
Chrome 267,716 II 0,1 0,01 1 0,1
205,552 II 0,3 0,03
206,149 II
283,563 II 0,2 0,02
284,325 II
Cobalt 238,892 II 0,4 0,04 1,2 0,1
228,616 II 0,4 0,04 1 0,1
230,786 II
Cuivre 327,396 I 0,3 0,03 1,5 0,1
224,700 II
324,754 I 0,6 0,06
Fer 238,204 II 0,3 0,03 0,9 0,09
239,562 II
259,940 II 0,5 0,05 0,7 0,07
Plomb 220,353 II 0,4 0,04 8 0,8
216,999 I
224,688 I
261,418 I
283,306 I 1,8 0,18
Lithium 670,783 I 1,7 0,17 1 0,1
460,286 I 67 6,7
Magnésium 279,553 II 0,02 0,002 0,1 0,01
279,079 II 1 0,1 4 0,4
285,213 I 0,06 0,006 0,25 0,025
279,806 II 1,5 0,15 10 1
Manganèse 257,610 II 0,10 0,01 0,13 0,01
260,569 II
279,482 II
293,306 II 0,4 0,04 1 0,1
403,076 I 0,8 0,08
259,372 ll 0,05 0,005
Mercure 194,227 II 1,2 0,12 2,5 0,25
253,652 I 1 0,1 2 0,20
184,890 I
Molybdène 202,030 II 0,2 0,02 2 0,2
204,598 II 0,6 0,06 3 0,3
Nickel 231,604 II 0,4 0,04 2,1 0,2
221,647 II 0,3 0,03 1,4 0,14
216,555 I 0,15 0,015
232,003 ll
4 © ISO 2008 – Tous droits réservés
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ISO 22036:2008(F)
Tableau 1 (suite)
Longueurs d'ondes et raies d'analyse Observation axiale Observation radiale
de l'élément
Élément Longueur Raies Limite de Limite de Limite de Limite de
d'onde détection détection détection détection
I = atome
a b a b
nm II = ion µg/l mg/kg µg/l mg/kg
Phosphore 177,428 I 1,5 0,15 25 2,5
178,222 I 7 0,7
213,618 I 1,3 0,13 5,3 0,53
214,914 l 1 0,1 11 1,1
Potassium 766,491 I 0,2 0,02 4 0,4
769,896 I 23 2,3 12 1,2
Rubidium 780,03 I 1 0,1 5 0,5
Sélénium 196,026 I 0,8 0,08 16 1,6
203,985 I 2,8 0,28
Silicium 251,611 I 0,9 0,09 2,2 0,22
212,412 I 1,3 0,13 5 0,5
288,158 I 1 0,1
Argent 328,068 I 0,4 0,04 1 0,1
338,289 I 1 0,1 2 0,2
Sodium 589,592 I 0,6 0,06 1,5 0,2
588,995 I 12 1,2 15 0,15
330,237 I 69 6,9
Strontium 407,771 II 0,01 0,001 0,1 0,01
421,552 II 0,01 0,001 0,1 0,01
460,733 I 0,3 0,03
Soufre 181,962 I 4 0,4 13 1,3
182,036
Thallium 190,800 II 2 0,2 13 0,1
190,864 II
Étain 189,933 II 6 0,6 8 0,8
235,484 I 23 2,3 20 2,0
283,998 l 11
Titane 336,121 II 0,15 0,015 1 0,1
334,941 II 0,2 0,02 0,25 0,25
337,280 II 0,2 0,02 1 0,1
Vanadium 292,402 II 0,3 0,03 2 0,2
309,310 II 0,08 0,008
311,837 II 0,1 0,01
290,882 ll
310,230 ll
Zinc 213,856 I 0,05 0,005 0,8 0,08
202,548 II 0,03 0,003 0,7 0,07
206,200 ll 0,15 0,015 2 0,02
Limites de détection types à 3 sigmas utilisant un temps d'intégration de 30 s.

La limite de détection (LOD) en fraction massique de l'échantillon de sol en mg/kg de matière sèche est indiquée, en supposant

qu'un échantillon pour essai de 1 g est extrait et dilué dans un volume de 100 ml. Les limites de détection indiquées dans le Tableau 1

constituent uniquement des exemples d'un équipement et de conditions de laboratoire donnés. Chaque laboratoire doit choisir des

longueurs d'ondes appropriées et déterminer la limite de détection dans ses conditions de fonctionnement spécifiques.

NOTE Bien que les longueurs d'ondes indiquées dans le Tableau 1 soient souvent utilisées, elles sont données dans

le cas présent uniquement en tant qu'exemple. Il est possible d'utiliser d'autres longueurs d'ondes. Pour chaque élément,

la limite de détection et le domaine de linéarité varient avec la longueur d'onde, le spectromètre, les conditions de

fonctionnement et la matrice de la solution échantillon. Le mesurage de solutions contenant des concentrations en sel

élevées (ce qui est généralement le cas pour des solutions d'extrait de sol) entraîne une augmentation importante de la

limite de détection par comparaison avec des échantillons d'eau.
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ISO 22036:2008(F)

La présente Norme internationale se réfère plus spécifiquement à l'utilisation de la spectrométrie d'émission

atomique avec plasma induit par haute fréquence. Il est recommandé aux utilisateurs de la présente Norme

internationale d'exploiter leurs résultats selon des modes opératoires de contrôle de la qualité admis. Il

convient d'utiliser des matériaux de référence certifiés (MRC) de manière à déterminer les quantités des

éléments appropriés dans les matériaux de référence utilisés en interne. Ces derniers peuvent être utilisés

pour un contrôle de la qualité régulier des modes opératoires définis dans la présente Norme internationale.

Chaque laboratoire doit établir les résultats pour chaque élément au moyen de cartes de contrôle. Aucun

résultat en dehors d'une limite admise ne doit être accepté. Les modes opératoires de contrôle de la qualité

basés sur des techniques statistiques largement admises doivent servir à établir des limites stables et

permettre d'établir qu'aucune dérive de longue durée ne se produit. Il convient d'utiliser des matériaux de

référence certifiés de manière régulière afin de maintenir l'intégrité des matériaux de référence internes et, de

ce fait, le système de contrôle de la qualité.
5 Interférences
5.1 Généralités

La présence de différents éléments de matrice dans la solution échantillon peut provoquer de sévères

interférences, qui induisent des erreurs systématiques sur le signal de l'analyte. Des techniques particulières,

par exemple correction du bruit de fond, éléments concomitants dans la solution d'étalonnage ou méthode

des ajouts dosés, peuvent être utilisées pour compenser ces interférences.

Les interférences sont classées en interférences spectrales et non spectrales. Elles peuvent être également

spécifiques ou non spécifiques à un analyte.

Les interférences spectrales (voir 5.2) sont dues à un isolement incomplet du rayonnement émis par l'analyte

d'autres sources de rayonnement détectées et amplifiées par le système de détection (interférences

additives).

Les interférences non spectrales (voir 5.3) sont les interférences avec lesquelles la sensibilité varie du fait de

la composition des solutions à mesurer (interférences multiplicatives). L'effet de matrice observé est une

interférence composite due à l'ensemble des composants dans la solution échantillon.

Le dosage des éléments traces nécessite une correction du bruit de fond. L'émission du bruit de fond doit être

mesurée parallèlement aux raies d'émission de l'analyte sur des échantillons au cours de l'analyse. La

position choisie pour la mesure de l'intensité du bruit de fond, sur l'un des côtés ou les deux côtés de la raie

d'analyse, est déterminée par la complexité du spectre contigu à la raie d'émission de l'analyte. Il convient

que la position utilisée soit la plus indépendante possible de l'interférence spectrale, et qu'elle reflète la même

variation de l'intensité du bruit de fond observée au niveau de la longueur d'onde de l'analyte mesurée.

L'augmentation du bruit de fond est plus importante avec des instruments à observation axiale. La correction

du bruit de fond n'est pas requise dans le cas d'un élargissement des raies d'émission lorsque la mesure de la

correction du bruit de fond risque de détériorer effectivement le résultat de l'analyse.

5.2 Interférences spectrales
Des exemples d'interférences spectrales sont:

⎯ le recouvrement partiel ou complet d'une raie d'émission d'un autre élément avec celle de l'analyte; cas

particulier: augmentation du bruit de fond due à un épaulement d'une raie d'émission forte située à

proximité immédiate, par exemple décalage de bruit de fond pour Pb 220,353 nm sous l'effet

de Al 220,463 nm;

⎯ le recouvrement d'une bande moléculaire d'une particule multi atomique formée dans le plasma à partir

du solvant, de l'air ambiant ou des gaz (par exemple N , NO, NH, OH, CN) en association avec la raie

d'émission d'un analyte;
6 © ISO 2008 – Tous droits réservés
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ISO 22036:2008(F)

⎯ l'augmentation du bruit de fond due à des phénomènes de recombinaison, par exemple ensemble

d'éléments homogènes émis par Al entre 190 nm et 220 nm;
⎯ l'augmentation du bruit de fond due à la lumière parasite.

Le recouvrement d'une raie spectrale conduit habituellement à choisir une raie alternative. Si cela n'est pas

possible, des modes opératoires de correction mathématiques (par exemple technique de correction

inter-éléments, ajustement spectral multicomposés) peuvent être utilisées pour compenser l'interférence. La

correction du bruit de fond permet de compenser un décalage parallèle du bruit de fond. L'utilisation de deux

points de correction du bruit de fond de chaque côté de la crête permet de corriger un décalage de bruit de

fond oblique.

Les raies les plus importantes des analytes As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Tl et Zn ont été utilisées pour

l'étude des interférences spectrales des extraits de sol obtenus avec de l'eau régale. Les éléments de sol les

plus importants Al, As, Ca, Cr, Co, Cu, Fe, Mg, Mn, Mo, Ni, Ti, V et Zn ont servi d'éléments interférents dans

les deux concentrations suivantes: 100 mg/l et 500 mg/l. Ces concentrations d'éléments dans les sols sont

égales à 0,33 % et 1,67 % (en fraction massique) après extraction à l'eau régale effectuée conformément à

l'ISO 11466.

Les Tableaux B.1 et B.3 de l'Annexe B fournissent un résumé des interférences spectrales éventuelles

observées lors de l'analyse des extraits de sols obtenus avec de l'eau régale. Les tableaux indiquent l'élément

interférent ainsi que la raie d'émission pour chaque élément. Un instrument Perkin-Elmer Optima 3000 avec

une résolution spectrale de 0,006 nm à une longueur d'onde de 200 nm a été utilisé pour l'étude présentée

dans le Tableau B.1 et un instrument Varian Vista-PRO avec plasma axial a été utilisé pour le Tableau B.3.

Les coïncidences des raies, qui dépendent de la résolution spectrale du spectromètre, deviennent

uniquement perceptibles lorsque la concentration de l'élément interférent et l'analyte atteignent un niveau

critique.

Dans le Tableau B.2, l'interférence est exprimée comme équivalents de la concentration de l'analyte

(c'est-à-dire augmentation fausse positive des concentrations de l'analyte) avec une augmentation découlant

de l'élément interférent à 100 mg/l et 500 mg/l, respectivement. Les données fournies sont destinées à servir

de guide pour indiquer l'étendue de l'interférence éventuelle. Il convient que l'utilisateur sache que d'autres

instruments peuvent présenter des niveaux d'interférence quelque peu différents de ceux indiqués dans le

Tableau B.2, dans la mesure où les intensités varient avec la conception de l'instrument, les conditions de

fonctionnement, par exemple la puissance, le débit du gaz d'introduction et la hauteur d'observation.

Certaines interférences spectrales éventuelles observées pour les longueurs d'ondes recommandées au

moyen d'un instrument à observation axiale sont indiquées dans le Tableau B.3. Par exemple, si Cr doit être

déterminé avec une longueur d'onde de 267,716 nm dans un échantillon contenant environ 100 mg/l de Al,

cela produit un signal faux positif pour un niveau de Cr équivalent à environ 0,06 mg/l. Il convient que

l'utilisateur tienne compte du fait que d'autres instruments peuvent présenter des niveaux d'interférence

quelque peu différents de ceux indiqués dans le Tableau B.3. Les effets d'interférence doivent être évalués

pour chaque instrument individuel, qu'il soit configuré comme instrument séquentiel ou simultané. Pour

chaque instrument, les intensités varient non seulement avec la résolution optique, mais également avec les

conditions de fonctionnement (telles que la puissance, la hauteur d'observation et le débit d'argon). Lorsqu'il

utilise les longueurs d'ondes recommandées, l'analyste est appelé à déterminer et à indiquer, pour chaque

longueur d'onde, l'effet des interférences référencées (voir Tableau B.3) ainsi que de toutes autres

interférences présumées qui peuvent être spécifiques à l'instrument ou à la matrice. Il convient que l'analyste

utilise un programme informatique pour une correction automatique de toutes les analyses.

1) Perkin-Elmer Optima 3000 et Varian Vista-Pro sont des exemples de produits appropriés disponibles sur le marché.

Cette information est donnée à l'intention des utilisateurs de la présente Norme internationale et ne signifie nullement que

l'ISO approuve ou recommande l'emploi exclusif des produits ainsi désignés.
© ISO 2008 – Tous droits réservés 7
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ISO 22036:2008(F)
5.3 Interférences non spectrales

Les interférences non spectrales peuvent se produire lors de la nébulisation ou de l'introduction de

l'échantillon (nature physique), ou également dans le plasma proprement dit (nature à la fois physique et

chimique).

Les interférences liées au transport sont dues aux différences constatées au niveau des propriétés physiques

(viscosité, tension superficielle, masse volumique) entre les solutions d'échantillon pou

...

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