Soil quality - Determination of trace elements using inductively coupled plasma mass spectrometry (ICP-MS)

This Technical Specification specifies a method for the determination of the following elements in aqua
regia or nitric acid digests or other extraction solutions of sludge, treated biowaste and soil:
Aluminium (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), bismuth (Bi), boron
(B), cadmium (Cd), calcium (Ca), cerium (Ce), cesium (Cs), chromium (Cr), cobalt (Co), copper (Cu),
dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), gallium (Ga), germanium (Ge), gold (Au),
hafnium (Hf), holmium (Ho), indium (In), iridium (Ir), iron (Fe), lanthanum (La), lead (Pb), lithium (Li),
lutetium (Lu), magnesium (Mg), manganese (Mn), mercury (Hg), molybdenum (Mo), neodymium (Nd),
nickel (Ni), palladium (Pd), phosphorus (P), platinum (Pt), potassium (K), praseodymium (Pr), rhenium
(Re), rhodium (Rh), rubidium (Rb), ruthenium (Ru), samarium (Sm), scandium (Sc), selenium (Se),
silicon (Si), silver (Ag), sodium (Na), strontium (Sr), sulfur (S), tellurium (Te), terbium (Tb), thallium
(Tl), thorium (Th), thulium (Tm), tin (Sn), titanium (Ti), tungsten (W), uranium (U), vanadium (V),
ytterbium(Yb), yttrium (Y), zinc (Zn) and zirconium (Zr).
The working range depends on the matrix and the interferences encountered.
The limit of detection is between 0,1 mg/kg dry matter and 2,0 mg/kg dry matter for most elements.
The limit of detection will be higher in cases where the determination is likely to have interferences (see
Clause 4) or in the case of memory effects (see e.g. 8.2 of ISO 17294-1:2004).

Qualité du sol - Détermination des éléments en traces par spectrométrie de masse avec plasma induit par haute fréquence (ICP-MS)

Kakovost tal - Določevanje elementov v sledovih z masno spektrometrijo z induktivno sklopljeno plazmo (ICP-MS)

Ta tehnična specifikacija opredeljuje metodo za določevanje naslednjih elementov v zlatotopki ali razklopu dušikove kisline ali drugih ekstrakcijskih raztopinah blata, obdelanih bioloških odpadkov in tal:
aluminij (Al), antimon (Sb), arzen (As), barij (Ba), berilij (Be), bizmut (Bi), bor (B), kadmij (Cd), kalcij (Ca), cerij (Ce), cezij (Cs), krom (Cr), kobalt (Co), baker (Cu), disprozij (Dy), erbij (Er), evropij (Eu), gadolinij (Gd), galij (Ga), germanij (Ge), zlato (Au), hafnij (Hf), holmij (Ho), indij (In), iridij (Ir), železo (Fe), lantan (La), svinec (Pb), litij (Li), lutecij (Lu), magnezij (Mg), mangan (Mn), živo srebro (Hg), molibden (Mo), neodim (Nd), nikelj (Ni), paladij (Pd), fosfor (P), platina (Pt), kalij (K), prazeodim (Pr), renij (Re), rodij (Rh), rutenij (Ru), samarij (Sm), skandij (Sc), selen (Se), silicij (Si), srebro (Ag), natrij (Na), stroncij (Sr), žveplo (S), telurij (Te), terbij (Tb), talij (Tl), torij (Th), tulij (Tm), kositer (Sn), titan (Ti), volfram (W), uran (U), vanadij (V), iterbij (Yb), itrij (Y), cink (Zn) in cirkonij (Zr).
Delovni razpon je odvisen od matrice in motenj, ki se pojavijo.
Meja zaznavanja za večino elementov je med 0,1 in 2 mg/kg suhe snovi. Meja zaznavanja bo višja v primerih, ko je možnost motenj določevanja verjetna (glej točko 4), ali v primeru spominskih učinkov (glej npr. točko 8.2 standarda ISO 17294-1:2004).

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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SLOVENSKI STANDARD
oSIST-TS ISO/TS 16965:2019
01-maj-2019
WULMR].DNRYRVWWDO'RORþHYDQMHHOHPHQWRYYVOHGRYLK]PDVQRVSHNWURPH
LQGXNWLYQRVNORSOMHQRSOD]PR ,&306

Soil quality - Determination of trace elements using inductively coupled plasma mass

spectrometry (ICP-MS)

Qualité du sol - Détermination des éléments en traces par spectrométrie de masse avec

plasma induit par haute fréquence (ICP-MS)
Ta slovenski standard je istoveten z: ISO/TS 16965:2013
ICS:
13.080.10 .HPLMVNH]QDþLOQRVWLWDO Chemical characteristics of
soils
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
oSIST-TS ISO/TS 16965:2019 en

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

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oSIST-TS ISO/TS 16965:2019
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oSIST-TS ISO/TS 16965:2019
TECHNICAL ISO/TS
SPECIFICATION 16965
First edition
2013-09-15
Soil quality — Determination of trace
elements using inductively coupled
plasma mass spectrometry (ICP-MS)
Qualité du sol — Détermination des éléments en traces par spectrométrie
de masse avec plasma induit par haute fréquence (ICP-MS)
Reference number
ISO/TS 16965:2013(E)
ISO 2013
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oSIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013

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

or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior

written permission. Permission can be requested 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 2013 – All rights reserved
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oSIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(E)
Contents Page

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

Introduction ..................................................................................................................................................................................................................................v

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

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

3 Principle ........................................................................................................................................................................................................................ 1

4 Interferences ............................................................................................................................................................................................................ 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Spectral interferences ....................................................................................................................................................................... 2

5 Reagents ........................................................................................................................................................................................................................ 3

6 Apparatus ..................................................................................................................................................................................................................... 5

6.1 General requirements ....................................................................................................................................................................... 5

6.2 Mass spectrometer .............................................................................................................................................................................. 6

6.3 Mass-flow controller .......................................................................................................................................................................... 6

6.4 Nebuliser with variable speed peristaltic pump ........................................................................................................ 6

6.5 Gas supply ................................................................................................................................................................................................... 6

6.6 Storage bottles, for the stock, standard, calibration and sample solutions ........................................ 6

7 Procedure..................................................................................................................................................................................................................... 7

7.1 Test sample solution .......................................................................................................................................................................... 7

7.2 Test portion solution .......................................................................................................................................................................... 7

7.3 Instrument set up ................................................................................................................................................................................. 7

7.4 Calibration .................................................................................................................................................................................................. 8

7.5 Sample measurement ........................................................................................................................................................................ 8

8 Calculation .................................................................................................................................................................................................................. 9

9 Expression of results ........................................................................................................................................................................................ 9

10 Performance characteristics .................................................................................................................................................................10

10.1 General ........................................................................................................................................................................................................10

10.2 Blank .............................................................................................................................................................................................................10

10.3 Calibration check ................................................................................................................................................................................10

10.4 Internal standard response .......................................................................................................................................................10

10.5 Interference ............................................................................................................................................................................................10

10.6 Recovery ....................................................................................................................................................................................................10

10.7 Precision ....................................................................................................................................................................................................10

11 Test report ................................................................................................................................................................................................................11

Annex A (informative) Selected isotopes and spectral interferences for quadrupole ICP-

MS instruments ...................................................................................................................................................................................................12

Bibliography .............................................................................................................................................................................................................................13

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oSIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives

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. Details of any

patent rights identified during the development of the document will be in the Introduction and/or on

the ISO list of patent declarations received. www.iso.org/patents

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers

to Trade (TBT) see the following URL: Foreword - Supplementary information

The committee responsible for this document is ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical

methods and soil characteristics.
iv © ISO 2013 – All rights reserved
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oSIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(E)
Introduction

ISO/TS 16965 is based upon CEN/TS 16171, Sludge, treated biowaste and soil — Determination of elements

using inductively coupled plasma mass spectrometry (ICP-MS), which was developed by CEN/TC 400,

Project Committee — Horizontal standards in the fields of sludge, biowaste and soil.

This Technical Specification is applicable and validated for several types of matrices as indicated in Table 1.

Table 1 — Matrices for which this Technical Specification is applicable and validated

Matrix Materials used for validation
Sludge Municipal sludge
Biowaste Compost
Soil Sludge-amended soils
© ISO 2013 – All rights reserved v
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oSIST-TS ISO/TS 16965:2019
TECHNICAL SPECIFICATION ISO/TS 16965:2013(E)
Soil quality — Determination of trace elements using
inductively coupled plasma mass spectrometry (ICP-MS)

WARNING — Persons using this Technical Specification should be familiar with usual laboratory

practice. This Technical Specification does not purport to address all of the safety problems, if

any, associated with its use. It is the responsibility of the user to establish appropriate safety and

health practices and to ensure compliance with any national regulatory conditions.

IMPORTANT — It is absolutely essential that tests conducted according to this Technical

Specification be carried out by suitably trained staff.
1 Scope

This Technical Specification specifies a method for the determination of the following elements in aqua

regia or nitric acid digests or other extraction solutions of sludge, treated biowaste and soil:

Aluminium (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), bismuth (Bi), boron

(B), cadmium (Cd), calcium (Ca), cerium (Ce), cesium (Cs), chromium (Cr), cobalt (Co), copper (Cu),

dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), gallium (Ga), germanium (Ge), gold (Au),

hafnium (Hf), holmium (Ho), indium (In), iridium (Ir), iron (Fe), lanthanum (La), lead (Pb), lithium (Li),

lutetium (Lu), magnesium (Mg), manganese (Mn), mercury (Hg), molybdenum (Mo), neodymium (Nd),

nickel (Ni), palladium (Pd), phosphorus (P), platinum (Pt), potassium (K), praseodymium (Pr), rhenium

(Re), rhodium (Rh), rubidium (Rb), ruthenium (Ru), samarium (Sm), scandium (Sc), selenium (Se),

silicon (Si), silver (Ag), sodium (Na), strontium (Sr), sulfur (S), tellurium (Te), terbium (Tb), thallium

(Tl), thorium (Th), thulium (Tm), tin (Sn), titanium (Ti), tungsten (W), uranium (U), vanadium (V),

ytterbium(Yb), yttrium (Y), zinc (Zn) and zirconium (Zr).
The working range depends on the matrix and the interferences encountered.

The limit of detection is between 0,1 mg/kg dry matter and 2,0 mg/kg dry matter for most elements.

The limit of detection will be higher in cases where the determination is likely to have interferences (see

Clause 4) or in the case of memory effects (see e.g. 8.2 of ISO 17294-1:2004).
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 11466, Soil quality — Extraction of trace elements soluble in aqua regia
ISO 16729, Soil quality — Digestion of nitric acid soluble fractions of elements
ISO 3696, Water for analytical laboratory use — Specification and test methods

ISO 17294-1:2004, Water quality — Application of inductively coupled plasma mass spectrometry (ICP-

MS) — Part 1: General guidelines
3 Principle

Digests with nitric acid or aqua regia of samples of sludge, treated biowaste or soil (see ISO 11466 and

ISO 16729) are analysed by ICP-MS to get a multi-elemental determination of analytes.

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The method measures ions produced by a radio-frequency inductively coupled plasma. Analyte species

originating in the digest solution are nebulised and the resulting aerosol is transported by argon gas

into the plasma. The ions produced by the high temperatures of the plasma are entrained in the plasma

gas and introduced, by means of an interface, into a mass spectrometer, sorted according to their mass-

to-charge ratios and quantified with a detector (e.g. channel electron multiplier).

4 Interferences
4.1 General

Interferences shall be assessed and valid corrections applied. Interference correction shall include

compensation for background ions contributed by the plasma gas, reagents, and constituents of the

sample matrix.

Detailed information on spectral and non-spectral interferences is given in Clause 6 of ISO 17294-1:2004.

4.2 Spectral interferences
4.2.1 Isobaric elemental interferences

Isobaric elemental interferences are caused by isotopes of different elements of closely matched

nominal mass-to-charge ratio and which cannot be separated due to an insufficient resolution of the

114 114
mass spectrometer in use (e.g. Cd and Sn).

Element interferences from isobars may be corrected by taking into account the influence from the

interfering element (see ISO 17294-1:2004). The isotopes used for correction shall be free of interference

if possible. Correction options are often included in the software supplied with the instrument. Common

isobaric interferences are given in Table A.1.
4.2.2 Isobaric molecular and doubly-charged ion interferences

Isobaric molecular and doubly-charged ion interferences in ICP-MS are caused by ions consisting of more

40 35 + 40 35 + 75

than one atom or charge, respectively. Examples include Ar Cl and Ca Cl ion on the As signal

98 16 + 114 +

or Mo O ions on the Cd signal. Natural isotope abundances are available from the literature.

The accuracy of correction equations is based upon the constancy of the observed isotopic ratios for

the interfering species. Corrections that presume a constant fraction of a molecular ion relative to the

“parent” ion have not been found to be reliable, e.g. oxide levels can vary with operating conditions.

If a correction for an oxide ion is based upon the ratio of parent-to-oxide ion intensities, this shall be

determined by measuring the interference solution just before the sequence is started. The validity of

the correction coefficient should be checked at regular intervals within a sequence.

Another possibility to remove isobaric molecular interferences is the use of an instrument with

collision/reaction cell technology. The use of high resolution ICP-MS avoids these interferences and

additionally double-charged ion interferences.

The response of the analyte of interest shall be corrected for the contribution of isobaric molecular and

doubly-charged interferences if their impact can be higher than three times the detection limit or higher

than half the lowest concentration to be reported.
More information about the use of correction factors is given in ISO 17294-1.
4.2.3 Non-spectral interferences

Physical interferences are associated with sample nebulisation and transport processes as well as

with ion-transmission efficiencies. Nebulisation and transport processes can be affected if a matrix

component causes a change in surface tension or viscosity. Changes in matrix composition can cause

2 © ISO 2013 – All rights reserved
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significant signal suppression or enhancement. Solids can be deposited on the nebuliser tip of a

pneumatic nebuliser and on the cones.

It is recommended to keep the level of total dissolved solids below 0,2 % (2 000 mg/l) to minimize

deposition of solids in the sample introduction system of the plasma torch. An internal standard can be

used to correct for physical interferences if it is carefully matched to the analyte, so that the two elements

are similarly affected by matrix changes. Other possibilities to minimize non-spectral interferences are

matrix matching, particularly matching of the acid concentration, and standard addition.

When intolerable physical interferences are present in a sample, a significant suppression of the internal

standard signals (to less than 30 % of the signals in the calibration solution) will be observed. Dilution

of the sample (e.g. fivefold) usually eliminates the problem.
5 Reagents

For the determination of elements at trace and ultra trace level, the reagents shall be of adequate purity.

The concentration of the analyte or interfering substances in the reagents and the water should be

negligible compared to the lowest concentration to be determined.

Preferably, nitric acid preservation should be applied in order to minimize interferences by chloropolyatom

molecules. Bi, Hg, Hf, Mo, Sn, Sb, Te, W and Zr may need hydrochloric acid for preservation.

5.1 Water, grade 1 as specified in ISO 3696 for all sample preparations and dilutions.

5.2 Nitric acid, c(HNO ) = 15 mol/l.

NOTE Nitric acid is available both as c(HNO ) ≈ 1,4 g/ml [w(HNO ) = 650 g/kg] and c(HNO ) = 1,42 g/ml

3 3 3

[w(HNO ) ≈ 720 g/kg]. Both are suitable for use in this method, provided the content of the analytes of

interest is minimal.
5.3 Hydrochloric acid, c(HCl) = 12 mol/l, ρ ≈ 1,18 g/ml.
5.4 Single-element standard stock solutions

For Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, K, La, Li,

Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Tb, Te, Th, Ti, Tl, Tm,

U, V, W, Y, Yb, Zn, Zr, ρ = 1 000 mg/l each.

Both single-element standard stock solutions and multi-element standard stock solutions with adequate

specification stating the acid used and the preparation technique are commercially available.

These solutions are considered to be stable for more than one year, but in reference to guaranteed

stability, the recommendations of the manufacturer should be considered.
5.5 Anion standard stock solutions
−−3 2−
Cl ,,PO SO , ρ = 1 000 mg/l each.
4 4

Prepare these solutions from the respective acids. The solutions are commercially available.

These solutions are considered to be stable for more than one year, but in reference to guaranteed

stability, the recommendations of the manufacturer should be considered.
5.6 Multi-element standard stock solutions

Depending on the scope, different multi-element standard stock solutions may be necessary. In general,

when combining multi-element standard stock solutions, their chemical compatibility and the possible

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oSIST-TS ISO/TS 16965:2019
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hydrolysis of the components shall be regarded. Care shall be taken to prevent chemical reactions (e.g.

precipitation).

The multi-element standard stock solutions are considered to be stable for several months if stored in

the dark. This does not apply to multi-element standard stock solutions that are prone to hydrolysis, in

particular solutions of Bi, Mo, Sn, Sb, Te, W, Hf and Zr.

Mercury standard stock solutions can be stabilized by adding 1 mg/l Au in nitric acid (5.2) or by adding

hydrochloric acid (5.3) up to 0,6 %.

NOTE When Au is to be used as modifier, the instrument is not suitable for accurate Au determination.

Multi-element standard stock solutions with more elements are allowed provided that these

solutions are stable.

5.6.1 Multi-element standard stock solution A at the mg/l level may contain the following elements:

Ag, Al, As, B, Ba, Be, Bi, Cd, Ce, Co, Cr, Cu, Fe, Hg, Li, Mn, Nd, Ni, Pb, Pr, Sc, Se, Si, Sm, Sr, Te, Th, Ti, Tl, U, V, Zn.

Use nitric acid (5.2) for stabilization of multi-element standard stock solution A.

Other elements of interest may be added to the standard stock solution, provided that these solutions

are stable.

5.6.2 Multi-element standard stock solution B at the mg/l level may contain the following elements:

Mo, Sb, Si, Sn, W, Zr.

Use hydrochloric acid (5.3) for stabilization of multi-element standard stock solution B.

Other elements of interest may be added to the standard stock solution, provided that these solutions

are stable.

5.6.3 Multi-element standard stock solution C at the mg/l level may contain the following elements:

Ca, Mg, Na, K, P, S.

Use nitric acid (5.2) for stabilization of multi-element standard stock solution C.

5.7 Multi-element calibration solutions

Prepare in one or more steps calibration solutions at the highest concentration of interest. If more

concentration levels are needed prepare those similarly.
Add acids (5.2 and 5.3) to match the acid concentration of samples closely.

If traceability of the values is not established check the validity by comparison with a (traceable)

independent standard.
Check the stability of the diluted calibration solutions.
5.8 Internal standard solution

Internal standards can either be added to every flask or added online. It is essential that the same

concentration of internal standard is added to all standards. The elements In, Lu, Re, Ge and Rh have

been found suitable for this purpose.

The choice of elements for the internal standard solution depends on the analytical problem. The

solution of this/these internal standard(s) should cover the mass range of interest. The concentrations

of the selected elements (used as internal standard) should be negligibly low in the digests of samples.

4 © ISO 2013 – All rights reserved
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oSIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(E)

Generally, a suitable final concentration of the internal standard in samples and calibration solutions is

1 µg/l to 50 µg/l (for a high and stable count rate). The use of a collision/reaction cell may require higher

concentrations.
5.9 Calibration blank solution

Prepare the calibration blank solution by diluting acids (5.2, 5.3) with water (5.1) to the same

concentrations as used in the calibration solutions and samples.
5.10 Test blank solution

The test blank solution shall contain all of the reagents in the same volumes and handled in the same way

throughout the procedure as the samples. The test blank solution contains the same acid concentration

in the final solution as the test solution after the digestion method is applied.

5.11 Optimization solution

The optimization solution serves for mass calibration and for optimization of the instrumental settings,

e.g. adjustment of maximal sensitivity with respect to minimal oxide formation rate and minimal

formation of doubly charged ions. It should contain elements covering the total mass range, as well as

elements prone to a high oxide formation rate or to the formation of doubly charged ions. The composition

of the optimization depends on the elements of interest, instrument and manufacturer’s instructions.

An optimization solution containing e.g. Mg, Cu, Rh, In, Ba, La, Ce, U and Pb is suitable. Li, Be and Bi are

less suitable because they tend to cause memory effects at higher concentrations.

The mass concentrations of the elements used for optimization should allow count rates of more than

10 counts per second.
5.12 Interference check solution

The interference check solutions serve to determine the correction factors for the corresponding

equations. High demands are made concerning the purity of the basic reagents due to the high mass

concentrations.

Interference check solutions shall contain all the interferences of practical relevance given in ISO 17294-1,

at a concentration level at the same range as expected in the samples (see also 10.5).

Leaving out an interfering element according to ISO 17294-1 is permitted if it can be demonstrated that

its impact is negligible and lasting.

In extraordinary situations the other interfering elements according to ISO 17294-1 shall also be

investigated for relevance.
EXAMPLE An example of the composition of an interference check solution is:
– 3– 2–
ρ(Ca) = 2 500 mg/l; ρ(Cl ) = 2 000 mg/l; ρ(PO ) = 500 mg/l and ρ(SO ) = 500 mg/l
4 4
and for digests also
[1]

ρ(C) = 1 000 mg/l; ρ(Fe) = 500 mg/l; ρ(Na) = 500 mg/l and ρ(Al) = 500 mg/l (see ).

6 Apparatus
6.1 General requirements

The stability of samples, measuring, and calibration solutions depends to a high degree on the container

material. The material shall be checked according to the specific purpose. For the determination of

elements in a very low concentration range (<1 µg/kg), glass or polyvinyl chloride (PVC) should not

be used. Instead, it is recommended to use perfluoroalkoxy (PFA), hexafluoroethene propene (FEP) or

© ISO 2013 – All rights reserved 5
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oSIST-TS ISO/TS 16965:2019
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quartz containers, cleaned with diluted, high quality nitric acid or hot, concentrated nitric acid in a

closed system. For the determination of elements in a higher concentration range, containers made from

high density polyethylene (HDPE) or polytetrafluoroethene (PTFE) are also suited for the collection of

samples. Immediately before use, all containers should be washed thoroughly with diluted nitric acid

(e.g. w(HNO ) = 10 %), and then rinsed several times with water (5.1).

The limit of detection of most elements is affected by contamination of solutions and this depends

predominantly on the cleanliness of laboratory air.

The use of piston pipettes is permitted and also enables the preparation of smaller volumes of calibration

solutions. The application of dilutors is also allowed. Every charge of pipette tips and single-use plastics

vessels shall be tested for impurities.

Dispensing of a volume of less than 50 µl by means of a pipette should be avoided.

For more detailed information on the instrumentation see Clause 5 of ISO 17294-1:2004.

6.2 Mass spectrometer
A mass spectrometer with inductively coupled plasma (ICP) suitable
...

TECHNICAL ISO/TS
SPECIFICATION 16965
First edition
2013-09-15
Soil quality — Determination of trace
elements using inductively coupled
plasma mass spectrometry (ICP-MS)
Qualité du sol — Détermination des éléments en traces par spectrométrie
de masse avec plasma induit par haute fréquence (ICP-MS)
Reference number
ISO/TS 16965:2013(E)
ISO 2013
---------------------- Page: 1 ----------------------
ISO/TS 16965:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013

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

or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior

written permission. Permission can be requested 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 2013 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TS 16965:2013(E)
Contents Page

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

Introduction ..................................................................................................................................................................................................................................v

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

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

3 Principle ........................................................................................................................................................................................................................ 1

4 Interferences ............................................................................................................................................................................................................ 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Spectral interferences ....................................................................................................................................................................... 2

5 Reagents ........................................................................................................................................................................................................................ 3

6 Apparatus ..................................................................................................................................................................................................................... 5

6.1 General requirements ....................................................................................................................................................................... 5

6.2 Mass spectrometer .............................................................................................................................................................................. 6

6.3 Mass-flow controller .......................................................................................................................................................................... 6

6.4 Nebuliser with variable speed peristaltic pump ........................................................................................................ 6

6.5 Gas supply ................................................................................................................................................................................................... 6

6.6 Storage bottles, for the stock, standard, calibration and sample solutions ........................................ 6

7 Procedure..................................................................................................................................................................................................................... 7

7.1 Test sample solution .......................................................................................................................................................................... 7

7.2 Test portion solution .......................................................................................................................................................................... 7

7.3 Instrument set up ................................................................................................................................................................................. 7

7.4 Calibration .................................................................................................................................................................................................. 8

7.5 Sample measurement ........................................................................................................................................................................ 8

8 Calculation .................................................................................................................................................................................................................. 9

9 Expression of results ........................................................................................................................................................................................ 9

10 Performance characteristics .................................................................................................................................................................10

10.1 General ........................................................................................................................................................................................................10

10.2 Blank .............................................................................................................................................................................................................10

10.3 Calibration check ................................................................................................................................................................................10

10.4 Internal standard response .......................................................................................................................................................10

10.5 Interference ............................................................................................................................................................................................10

10.6 Recovery ....................................................................................................................................................................................................10

10.7 Precision ....................................................................................................................................................................................................10

11 Test report ................................................................................................................................................................................................................11

Annex A (informative) Selected isotopes and spectral interferences for quadrupole ICP-

MS instruments ...................................................................................................................................................................................................12

Bibliography .............................................................................................................................................................................................................................13

© ISO 2013 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/TS 16965:2013(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives

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. Details of any

patent rights identified during the development of the document will be in the Introduction and/or on

the ISO list of patent declarations received. www.iso.org/patents

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers

to Trade (TBT) see the following URL: Foreword - Supplementary information

The committee responsible for this document is ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical

methods and soil characteristics.
iv © ISO 2013 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TS 16965:2013(E)
Introduction

ISO/TS 16965 is based upon CEN/TS 16171, Sludge, treated biowaste and soil — Determination of elements

using inductively coupled plasma mass spectrometry (ICP-MS), which was developed by CEN/TC 400,

Project Committee — Horizontal standards in the fields of sludge, biowaste and soil.

This Technical Specification is applicable and validated for several types of matrices as indicated in Table 1.

Table 1 — Matrices for which this Technical Specification is applicable and validated

Matrix Materials used for validation
Sludge Municipal sludge
Biowaste Compost
Soil Sludge-amended soils
© ISO 2013 – All rights reserved v
---------------------- Page: 5 ----------------------
TECHNICAL SPECIFICATION ISO/TS 16965:2013(E)
Soil quality — Determination of trace elements using
inductively coupled plasma mass spectrometry (ICP-MS)

WARNING — Persons using this Technical Specification should be familiar with usual laboratory

practice. This Technical Specification does not purport to address all of the safety problems, if

any, associated with its use. It is the responsibility of the user to establish appropriate safety and

health practices and to ensure compliance with any national regulatory conditions.

IMPORTANT — It is absolutely essential that tests conducted according to this Technical

Specification be carried out by suitably trained staff.
1 Scope

This Technical Specification specifies a method for the determination of the following elements in aqua

regia or nitric acid digests or other extraction solutions of sludge, treated biowaste and soil:

Aluminium (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), bismuth (Bi), boron

(B), cadmium (Cd), calcium (Ca), cerium (Ce), cesium (Cs), chromium (Cr), cobalt (Co), copper (Cu),

dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), gallium (Ga), germanium (Ge), gold (Au),

hafnium (Hf), holmium (Ho), indium (In), iridium (Ir), iron (Fe), lanthanum (La), lead (Pb), lithium (Li),

lutetium (Lu), magnesium (Mg), manganese (Mn), mercury (Hg), molybdenum (Mo), neodymium (Nd),

nickel (Ni), palladium (Pd), phosphorus (P), platinum (Pt), potassium (K), praseodymium (Pr), rhenium

(Re), rhodium (Rh), rubidium (Rb), ruthenium (Ru), samarium (Sm), scandium (Sc), selenium (Se),

silicon (Si), silver (Ag), sodium (Na), strontium (Sr), sulfur (S), tellurium (Te), terbium (Tb), thallium

(Tl), thorium (Th), thulium (Tm), tin (Sn), titanium (Ti), tungsten (W), uranium (U), vanadium (V),

ytterbium(Yb), yttrium (Y), zinc (Zn) and zirconium (Zr).
The working range depends on the matrix and the interferences encountered.

The limit of detection is between 0,1 mg/kg dry matter and 2,0 mg/kg dry matter for most elements.

The limit of detection will be higher in cases where the determination is likely to have interferences (see

Clause 4) or in the case of memory effects (see e.g. 8.2 of ISO 17294-1:2004).
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 11466, Soil quality — Extraction of trace elements soluble in aqua regia
ISO 16729, Soil quality — Digestion of nitric acid soluble fractions of elements
ISO 3696, Water for analytical laboratory use — Specification and test methods

ISO 17294-1:2004, Water quality — Application of inductively coupled plasma mass spectrometry (ICP-

MS) — Part 1: General guidelines
3 Principle

Digests with nitric acid or aqua regia of samples of sludge, treated biowaste or soil (see ISO 11466 and

ISO 16729) are analysed by ICP-MS to get a multi-elemental determination of analytes.

© ISO 2013 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/TS 16965:2013(E)

The method measures ions produced by a radio-frequency inductively coupled plasma. Analyte species

originating in the digest solution are nebulised and the resulting aerosol is transported by argon gas

into the plasma. The ions produced by the high temperatures of the plasma are entrained in the plasma

gas and introduced, by means of an interface, into a mass spectrometer, sorted according to their mass-

to-charge ratios and quantified with a detector (e.g. channel electron multiplier).

4 Interferences
4.1 General

Interferences shall be assessed and valid corrections applied. Interference correction shall include

compensation for background ions contributed by the plasma gas, reagents, and constituents of the

sample matrix.

Detailed information on spectral and non-spectral interferences is given in Clause 6 of ISO 17294-1:2004.

4.2 Spectral interferences
4.2.1 Isobaric elemental interferences

Isobaric elemental interferences are caused by isotopes of different elements of closely matched

nominal mass-to-charge ratio and which cannot be separated due to an insufficient resolution of the

114 114
mass spectrometer in use (e.g. Cd and Sn).

Element interferences from isobars may be corrected by taking into account the influence from the

interfering element (see ISO 17294-1:2004). The isotopes used for correction shall be free of interference

if possible. Correction options are often included in the software supplied with the instrument. Common

isobaric interferences are given in Table A.1.
4.2.2 Isobaric molecular and doubly-charged ion interferences

Isobaric molecular and doubly-charged ion interferences in ICP-MS are caused by ions consisting of more

40 35 + 40 35 + 75

than one atom or charge, respectively. Examples include Ar Cl and Ca Cl ion on the As signal

98 16 + 114 +

or Mo O ions on the Cd signal. Natural isotope abundances are available from the literature.

The accuracy of correction equations is based upon the constancy of the observed isotopic ratios for

the interfering species. Corrections that presume a constant fraction of a molecular ion relative to the

“parent” ion have not been found to be reliable, e.g. oxide levels can vary with operating conditions.

If a correction for an oxide ion is based upon the ratio of parent-to-oxide ion intensities, this shall be

determined by measuring the interference solution just before the sequence is started. The validity of

the correction coefficient should be checked at regular intervals within a sequence.

Another possibility to remove isobaric molecular interferences is the use of an instrument with

collision/reaction cell technology. The use of high resolution ICP-MS avoids these interferences and

additionally double-charged ion interferences.

The response of the analyte of interest shall be corrected for the contribution of isobaric molecular and

doubly-charged interferences if their impact can be higher than three times the detection limit or higher

than half the lowest concentration to be reported.
More information about the use of correction factors is given in ISO 17294-1.
4.2.3 Non-spectral interferences

Physical interferences are associated with sample nebulisation and transport processes as well as

with ion-transmission efficiencies. Nebulisation and transport processes can be affected if a matrix

component causes a change in surface tension or viscosity. Changes in matrix composition can cause

2 © ISO 2013 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/TS 16965:2013(E)

significant signal suppression or enhancement. Solids can be deposited on the nebuliser tip of a

pneumatic nebuliser and on the cones.

It is recommended to keep the level of total dissolved solids below 0,2 % (2 000 mg/l) to minimize

deposition of solids in the sample introduction system of the plasma torch. An internal standard can be

used to correct for physical interferences if it is carefully matched to the analyte, so that the two elements

are similarly affected by matrix changes. Other possibilities to minimize non-spectral interferences are

matrix matching, particularly matching of the acid concentration, and standard addition.

When intolerable physical interferences are present in a sample, a significant suppression of the internal

standard signals (to less than 30 % of the signals in the calibration solution) will be observed. Dilution

of the sample (e.g. fivefold) usually eliminates the problem.
5 Reagents

For the determination of elements at trace and ultra trace level, the reagents shall be of adequate purity.

The concentration of the analyte or interfering substances in the reagents and the water should be

negligible compared to the lowest concentration to be determined.

Preferably, nitric acid preservation should be applied in order to minimize interferences by chloropolyatom

molecules. Bi, Hg, Hf, Mo, Sn, Sb, Te, W and Zr may need hydrochloric acid for preservation.

5.1 Water, grade 1 as specified in ISO 3696 for all sample preparations and dilutions.

5.2 Nitric acid, c(HNO ) = 15 mol/l.

NOTE Nitric acid is available both as c(HNO ) ≈ 1,4 g/ml [w(HNO ) = 650 g/kg] and c(HNO ) = 1,42 g/ml

3 3 3

[w(HNO ) ≈ 720 g/kg]. Both are suitable for use in this method, provided the content of the analytes of

interest is minimal.
5.3 Hydrochloric acid, c(HCl) = 12 mol/l, ρ ≈ 1,18 g/ml.
5.4 Single-element standard stock solutions

For Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, K, La, Li,

Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Tb, Te, Th, Ti, Tl, Tm,

U, V, W, Y, Yb, Zn, Zr, ρ = 1 000 mg/l each.

Both single-element standard stock solutions and multi-element standard stock solutions with adequate

specification stating the acid used and the preparation technique are commercially available.

These solutions are considered to be stable for more than one year, but in reference to guaranteed

stability, the recommendations of the manufacturer should be considered.
5.5 Anion standard stock solutions
−−3 2−
Cl ,,PO SO , ρ = 1 000 mg/l each.
4 4

Prepare these solutions from the respective acids. The solutions are commercially available.

These solutions are considered to be stable for more than one year, but in reference to guaranteed

stability, the recommendations of the manufacturer should be considered.
5.6 Multi-element standard stock solutions

Depending on the scope, different multi-element standard stock solutions may be necessary. In general,

when combining multi-element standard stock solutions, their chemical compatibility and the possible

© ISO 2013 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO/TS 16965:2013(E)

hydrolysis of the components shall be regarded. Care shall be taken to prevent chemical reactions (e.g.

precipitation).

The multi-element standard stock solutions are considered to be stable for several months if stored in

the dark. This does not apply to multi-element standard stock solutions that are prone to hydrolysis, in

particular solutions of Bi, Mo, Sn, Sb, Te, W, Hf and Zr.

Mercury standard stock solutions can be stabilized by adding 1 mg/l Au in nitric acid (5.2) or by adding

hydrochloric acid (5.3) up to 0,6 %.

NOTE When Au is to be used as modifier, the instrument is not suitable for accurate Au determination.

Multi-element standard stock solutions with more eleme
...

SLOVENSKI STANDARD
SIST-TS ISO/TS 16965:2019
01-oktober-2019
Kakovost tal - Določevanje elementov v sledovih z masno spektrometrijo z
induktivno sklopljeno plazmo (ICP-MS)

Soil quality - Determination of trace elements using inductively coupled plasma mass

spectrometry (ICP-MS)

Qualité du sol - Détermination des éléments en traces par spectrométrie de masse avec

plasma induit par haute fréquence (ICP-MS)
Ta slovenski standard je istoveten z: ISO/TS 16965:2013
ICS:
13.080.10 Kemijske značilnosti tal Chemical characteristics of
soils
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
SIST-TS ISO/TS 16965:2019 en

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

---------------------- Page: 1 ----------------------
SIST-TS ISO/TS 16965:2019
---------------------- Page: 2 ----------------------
SIST-TS ISO/TS 16965:2019
TECHNICAL ISO/TS
SPECIFICATION 16965
First edition
2013-09-15
Soil quality — Determination of trace
elements using inductively coupled
plasma mass spectrometry (ICP-MS)
Qualité du sol — Détermination des éléments en traces par spectrométrie
de masse avec plasma induit par haute fréquence (ICP-MS)
Reference number
ISO/TS 16965:2013(E)
ISO 2013
---------------------- Page: 3 ----------------------
SIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013

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

or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior

written permission. Permission can be requested 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 2013 – All rights reserved
---------------------- Page: 4 ----------------------
SIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(E)
Contents Page

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

Introduction ..................................................................................................................................................................................................................................v

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

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

3 Principle ........................................................................................................................................................................................................................ 1

4 Interferences ............................................................................................................................................................................................................ 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Spectral interferences ....................................................................................................................................................................... 2

5 Reagents ........................................................................................................................................................................................................................ 3

6 Apparatus ..................................................................................................................................................................................................................... 5

6.1 General requirements ....................................................................................................................................................................... 5

6.2 Mass spectrometer .............................................................................................................................................................................. 6

6.3 Mass-flow controller .......................................................................................................................................................................... 6

6.4 Nebuliser with variable speed peristaltic pump ........................................................................................................ 6

6.5 Gas supply ................................................................................................................................................................................................... 6

6.6 Storage bottles, for the stock, standard, calibration and sample solutions ........................................ 6

7 Procedure..................................................................................................................................................................................................................... 7

7.1 Test sample solution .......................................................................................................................................................................... 7

7.2 Test portion solution .......................................................................................................................................................................... 7

7.3 Instrument set up ................................................................................................................................................................................. 7

7.4 Calibration .................................................................................................................................................................................................. 8

7.5 Sample measurement ........................................................................................................................................................................ 8

8 Calculation .................................................................................................................................................................................................................. 9

9 Expression of results ........................................................................................................................................................................................ 9

10 Performance characteristics .................................................................................................................................................................10

10.1 General ........................................................................................................................................................................................................10

10.2 Blank .............................................................................................................................................................................................................10

10.3 Calibration check ................................................................................................................................................................................10

10.4 Internal standard response .......................................................................................................................................................10

10.5 Interference ............................................................................................................................................................................................10

10.6 Recovery ....................................................................................................................................................................................................10

10.7 Precision ....................................................................................................................................................................................................10

11 Test report ................................................................................................................................................................................................................11

Annex A (informative) Selected isotopes and spectral interferences for quadrupole ICP-

MS instruments ...................................................................................................................................................................................................12

Bibliography .............................................................................................................................................................................................................................13

© ISO 2013 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives

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. Details of any

patent rights identified during the development of the document will be in the Introduction and/or on

the ISO list of patent declarations received. www.iso.org/patents

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers

to Trade (TBT) see the following URL: Foreword - Supplementary information

The committee responsible for this document is ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical

methods and soil characteristics.
iv © ISO 2013 – All rights reserved
---------------------- Page: 6 ----------------------
SIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(E)
Introduction

ISO/TS 16965 is based upon CEN/TS 16171, Sludge, treated biowaste and soil — Determination of elements

using inductively coupled plasma mass spectrometry (ICP-MS), which was developed by CEN/TC 400,

Project Committee — Horizontal standards in the fields of sludge, biowaste and soil.

This Technical Specification is applicable and validated for several types of matrices as indicated in Table 1.

Table 1 — Matrices for which this Technical Specification is applicable and validated

Matrix Materials used for validation
Sludge Municipal sludge
Biowaste Compost
Soil Sludge-amended soils
© ISO 2013 – All rights reserved v
---------------------- Page: 7 ----------------------
SIST-TS ISO/TS 16965:2019
---------------------- Page: 8 ----------------------
SIST-TS ISO/TS 16965:2019
TECHNICAL SPECIFICATION ISO/TS 16965:2013(E)
Soil quality — Determination of trace elements using
inductively coupled plasma mass spectrometry (ICP-MS)

WARNING — Persons using this Technical Specification should be familiar with usual laboratory

practice. This Technical Specification does not purport to address all of the safety problems, if

any, associated with its use. It is the responsibility of the user to establish appropriate safety and

health practices and to ensure compliance with any national regulatory conditions.

IMPORTANT — It is absolutely essential that tests conducted according to this Technical

Specification be carried out by suitably trained staff.
1 Scope

This Technical Specification specifies a method for the determination of the following elements in aqua

regia or nitric acid digests or other extraction solutions of sludge, treated biowaste and soil:

Aluminium (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), bismuth (Bi), boron

(B), cadmium (Cd), calcium (Ca), cerium (Ce), cesium (Cs), chromium (Cr), cobalt (Co), copper (Cu),

dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), gallium (Ga), germanium (Ge), gold (Au),

hafnium (Hf), holmium (Ho), indium (In), iridium (Ir), iron (Fe), lanthanum (La), lead (Pb), lithium (Li),

lutetium (Lu), magnesium (Mg), manganese (Mn), mercury (Hg), molybdenum (Mo), neodymium (Nd),

nickel (Ni), palladium (Pd), phosphorus (P), platinum (Pt), potassium (K), praseodymium (Pr), rhenium

(Re), rhodium (Rh), rubidium (Rb), ruthenium (Ru), samarium (Sm), scandium (Sc), selenium (Se),

silicon (Si), silver (Ag), sodium (Na), strontium (Sr), sulfur (S), tellurium (Te), terbium (Tb), thallium

(Tl), thorium (Th), thulium (Tm), tin (Sn), titanium (Ti), tungsten (W), uranium (U), vanadium (V),

ytterbium(Yb), yttrium (Y), zinc (Zn) and zirconium (Zr).
The working range depends on the matrix and the interferences encountered.

The limit of detection is between 0,1 mg/kg dry matter and 2,0 mg/kg dry matter for most elements.

The limit of detection will be higher in cases where the determination is likely to have interferences (see

Clause 4) or in the case of memory effects (see e.g. 8.2 of ISO 17294-1:2004).
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 11466, Soil quality — Extraction of trace elements soluble in aqua regia
ISO 16729, Soil quality — Digestion of nitric acid soluble fractions of elements
ISO 3696, Water for analytical laboratory use — Specification and test methods

ISO 17294-1:2004, Water quality — Application of inductively coupled plasma mass spectrometry (ICP-

MS) — Part 1: General guidelines
3 Principle

Digests with nitric acid or aqua regia of samples of sludge, treated biowaste or soil (see ISO 11466 and

ISO 16729) are analysed by ICP-MS to get a multi-elemental determination of analytes.

© ISO 2013 – All rights reserved 1
---------------------- Page: 9 ----------------------
SIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(E)

The method measures ions produced by a radio-frequency inductively coupled plasma. Analyte species

originating in the digest solution are nebulised and the resulting aerosol is transported by argon gas

into the plasma. The ions produced by the high temperatures of the plasma are entrained in the plasma

gas and introduced, by means of an interface, into a mass spectrometer, sorted according to their mass-

to-charge ratios and quantified with a detector (e.g. channel electron multiplier).

4 Interferences
4.1 General

Interferences shall be assessed and valid corrections applied. Interference correction shall include

compensation for background ions contributed by the plasma gas, reagents, and constituents of the

sample matrix.

Detailed information on spectral and non-spectral interferences is given in Clause 6 of ISO 17294-1:2004.

4.2 Spectral interferences
4.2.1 Isobaric elemental interferences

Isobaric elemental interferences are caused by isotopes of different elements of closely matched

nominal mass-to-charge ratio and which cannot be separated due to an insufficient resolution of the

114 114
mass spectrometer in use (e.g. Cd and Sn).

Element interferences from isobars may be corrected by taking into account the influence from the

interfering element (see ISO 17294-1:2004). The isotopes used for correction shall be free of interference

if possible. Correction options are often included in the software supplied with the instrument. Common

isobaric interferences are given in Table A.1.
4.2.2 Isobaric molecular and doubly-charged ion interferences

Isobaric molecular and doubly-charged ion interferences in ICP-MS are caused by ions consisting of more

40 35 + 40 35 + 75

than one atom or charge, respectively. Examples include Ar Cl and Ca Cl ion on the As signal

98 16 + 114 +

or Mo O ions on the Cd signal. Natural isotope abundances are available from the literature.

The accuracy of correction equations is based upon the constancy of the observed isotopic ratios for

the interfering species. Corrections that presume a constant fraction of a molecular ion relative to the

“parent” ion have not been found to be reliable, e.g. oxide levels can vary with operating conditions.

If a correction for an oxide ion is based upon the ratio of parent-to-oxide ion intensities, this shall be

determined by measuring the interference solution just before the sequence is started. The validity of

the correction coefficient should be checked at regular intervals within a sequence.

Another possibility to remove isobaric molecular interferences is the use of an instrument with

collision/reaction cell technology. The use of high resolution ICP-MS avoids these interferences and

additionally double-charged ion interferences.

The response of the analyte of interest shall be corrected for the contribution of isobaric molecular and

doubly-charged interferences if their impact can be higher than three times the detection limit or higher

than half the lowest concentration to be reported.
More information about the use of correction factors is given in ISO 17294-1.
4.2.3 Non-spectral interferences

Physical interferences are associated with sample nebulisation and transport processes as well as

with ion-transmission efficiencies. Nebulisation and transport processes can be affected if a matrix

component causes a change in surface tension or viscosity. Changes in matrix composition can cause

2 © ISO 2013 – All rights reserved
---------------------- Page: 10 ----------------------
SIST-TS ISO/TS 16965:2019
ISO/TS 16965:2013(E)

significant signal suppression or enhancement. Solids can be deposited on the nebuliser tip of a

pneumatic nebuliser and on the cones.

It is recommended to keep the level of total dissolved solids below 0,2 % (2 000 mg/l) to minimize

deposition of solids in the sample introduction system of the plasma torch. An internal standard can be

used to correct for physical interferences if it is carefully matched to the analyte, so that the two elements

are similarly affected by matrix changes. Other possibilities to minimize non-spectral interferences are

matrix matching, particularly matching of the acid concentration, and standard addition.

When intolerable physical interferences are present in a sample, a significant suppression of the internal

standard signals (to less than 30 % of the signals in the calibration solution) will be observed. Dilution

of the sample (e.g. fivefold) usually eliminates the problem.
5 Reagents

For the determination of elements at trace and ultra trace level, the reagents shall be of adequate purity.

The concentration of the analyte or interfering substances in the reagents and the water should be

negligible compared to the lowest concentration to be determined.

Preferably, nitric acid preservation should be applied in order to minimize interferences by chloropolyatom

molecules. Bi, Hg, Hf, Mo, Sn, Sb, Te, W and Zr may need hydrochloric acid for preservation.

5.1 Water, grade 1 as specified in ISO 3696 for all sample preparations and dilutions.

5.2 Nitric acid, c(HNO ) = 15 mol/l.

NOTE Nitric acid is available both as c(HNO ) ≈ 1,4 g/ml [w(HNO ) = 650 g/kg] and c(HNO ) = 1,42 g/ml

3 3 3

[w(HNO ) ≈ 720 g/kg]. Both are suitable for use in this method, provided the content of the analytes of

interest is minimal.
5.3 Hydrochloric acid, c(HCl) = 12 mol/l, ρ ≈ 1,18 g/ml.
5.4 Single-element standard stock solutions

For Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, K, La, Li,

Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Tb, Te, Th, Ti, Tl, Tm,

U, V, W, Y, Yb, Zn, Zr, ρ = 1 000 mg/l each.

Both single-element standard stock solutions and multi-element standard stock solutions with adequate

specification stating the acid used and the preparation technique are commercially available.

These solutions are considered to be stable for more than one year, but in reference to guaranteed

stability, the recommendations of the manufacturer should be considered.
5.5 Anion standard stock solutions
−−3 2−
Cl ,,PO SO , ρ = 1 000 mg/l each.
4 4

Prepare these solutions from the respective acids. The solutions are commercially available.

These solutions are considered to be stable for more than one year, but in reference to guaranteed

stability, the recommendations of the manufacturer should be considered.
5.6 Multi-element standard stock solutions

Depending on the scope, different multi-element standard stock solutions may be necessary. In general,

when combining multi-element standard stock solutions, their chemical compatibility and the possible

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hydrolysis of the components shall be regarded. Care shall be taken to prevent chemical reactions (e.g.

precipitation).

The multi-element standard stock solutions are considered to be stable for several months if stored in

the dark. This does not apply to multi-element standard stock solutions that are prone to hydrolysis, in

particular solutions of Bi, Mo, Sn, Sb, Te, W, Hf and Zr.

Mercury standard stock solutions can be stabilized by adding 1 mg/l Au in nitric acid (5.2) or by adding

hydrochloric acid (5.3) up to 0,6 %.

NOTE When Au is to be used as modifier, the instrument is not suitable for accurate Au determination.

Multi-element standard stock solutions with more elements are allowed provided that these

solutions are stable.

5.6.1 Multi-element standard stock solution A at the mg/l level may contain the following elements:

Ag, Al, As, B, Ba, Be, Bi, Cd, Ce, Co, Cr, Cu, Fe, Hg, Li, Mn, Nd, Ni, Pb, Pr, Sc, Se, Si, Sm, Sr, Te, Th, Ti, Tl, U, V, Zn.

Use nitric acid (5.2) for stabilization of multi-element standard stock solution A.

Other elements of interest may be added to the standard stock solution, provided that these solutions

are stable.

5.6.2 Multi-element standard stock solution B at the mg/l level may contain the following elements:

Mo, Sb, Si, Sn, W, Zr.

Use hydrochloric acid (5.3) for stabilization of multi-element standard stock solution B.

Other elements of interest may be added to the standard stock solution, provided that these solutions

are stable.

5.6.3 Multi-element standard stock solution C at the mg/l level may contain the following elements:

Ca, Mg, Na, K, P, S.

Use nitric acid (5.2) for stabilization of multi-element standard stock solution C.

5.7 Multi-element calibration solutions

Prepare in one or more steps calibration solutions at the highest concentration of interest. If more

concentration levels are needed prepare those similarly.
Add acids (5.2 and 5.3) to match the acid concentration of samples closely.

If traceability of the values is not established check the validity by comparison with a (traceable)

independent standard.
Check the stability of the diluted calibration solutions.
5.8 Internal standard solution

Internal standards can either be added to every flask or added online. It is essential that the same

concentration of internal standard is added to all standards. The elements In, Lu, Re, Ge and Rh have

been found suitable for this purpose.

The choice of elements for the internal standard solution depends on the analytical problem. The

solution of this/these internal standard(s) should cover the mass range of interest. The concentrations

of the selected elements (used as internal standard) should be negligibly low in the digests of samples.

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Generally, a suitable final concentration of the internal standard in samples and calibration solutions is

1 µg/l to 50 µg/l (for a high and stable count rate). The use of a collision/reaction cell may require higher

concentrations.
5.9 Calibration blank solution

Prepare the calibration blank solution by diluting acids (5.2, 5.3) with water (5.1) to the same

concentrations as used in the calibration solutions and samples.
5.10 Test blank solution

The test blank solution shall contain all of the reagents in the same volumes and handled in the same way

throughout the procedure as the samples. The test blank solution contains the same acid concentration

in the final solution as the test solution after the digestion method is applied.

5.11 Optimization solution

The optimization solution serves for mass calibration and for optimization of the instrumental settings,

e.g. adjustment of maximal sensitivity with respect to minimal oxide formation rate and minimal

formation of doubly charged ions. It should contain elements covering the total mass range, as well as

elements prone to a high oxide formation rate or to the formation of doubly charged ions. The composition

of the optimization depends on the elements of interest, instrument and manufacturer’s instructions.

An optimization solution containing e.g. Mg, Cu, Rh, In, Ba, La, Ce, U and Pb is suitable. Li, Be and Bi are

less suitable because they tend to cause memory effects at higher concentrations.

The mass concentrations of the elements used for optimization should allow count rates of more than

10 counts per second.
5.12 Interference check solution

The interference check solutions serve to determine the correction factors for the corresponding

equations. High demands are made concerning the purity of the basic reagents due to the high mass

concentrations.

Interference check solutions shall contain all the interferences of practical relevance given in ISO 17294-1,

at a concentration level at the same range as expected in the samples (see also 10.5).

Leaving out an interfering element according to ISO 17294-1 is permitted if it can be demonstrated that

its impact is negligible and lasting.

In extraordinary situations the other interfering elements according to ISO 17294-1 shall also be

investigated for relevance.
EXAMPLE An example of the composition of an interference check solution is:
– 3– 2–
ρ(Ca) = 2 500 mg/l; ρ(Cl ) = 2 000 mg/l; ρ(PO ) = 500 mg/l and ρ(SO ) = 500 mg/l
4 4
and for digests also
[1]

ρ(C) = 1 000 mg/l; ρ(Fe) = 500 mg/l; ρ(Na) = 500 mg/l and ρ(Al) = 500 mg/l (see ).

6 Apparatus
6.1 General requirements

The stability of samples, measuring, and calibration solutions depends to a high degree on the container

material. The material shall be checked according to the specific purpose. For the determination of

elements in a very low concentration range (<1 µg/kg), glass or polyvinyl chloride (PVC) should not

be used. Instead, it is recommended to use perfluoroalkoxy (PFA), hexafluoroethene propene (FEP) or

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quartz containers, cleaned with diluted, high quality nitric acid or hot, concentrated nitric acid in a

closed system. For the determination of elements in a higher concentration range, containers made from

high density polyethylene (HDPE) or polytetrafluoroethene (PTFE) are also suited for the collection of

samples. Immediately before use, all containers should be washed thoroughly with diluted nitric acid

(e.g. w(HNO ) = 10 %), and then rinsed several times with water (5.1).

The limit of detection of most elements is affected by contamination of solutions and this depends

predominantly on the cleanliness of laboratory air.

The use of piston pipettes is permitted and also enables the preparation of smaller volumes of calibration

solutions. The application of dilutors is also allowed. Every charge of pipette tips and single-use plastics

vessels shall be tested for impurities.

Dispensing of a volume of less than 50 µl by means of a pipette should be avoided.

For more detailed information on the instrumentation see Clause 5 of ISO 17294-1:2004.

6.2 Mass spectrometer

A mass spectrometer with inductively coupled plasma (ICP) suitable for multi-element and isotope

ana
...

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