Water quality - Determination of dissolved Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+ and Ba2+ using ion chromatography - Method for water and waste water (ISO 14911:1998)

Migrated from Progress Sheet (TC Comment) (2000-07-10): E-mail of 980119 to Safoura: as FDIS is almost ready, we can only follow with ++ a UAP but WHEN the ISO will be published (TA/980120) ++ Barz's fax dated 980917: CS requested to launch the UAP at the reception of the ++ German version (TA/980917)

Wasserbeschaffenheit - Bestimmung der gelösten Kationen Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+ und Ba2+ mittels Ionenchromatographie - Verfahren für Wasser und Abwasser (ISO 14911:1998)

Diese Internationale Norm legt ein Verfahren zur Bestimmung der gelösten Kationen Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+ und Ba2+ in Wasser (z.B. Trinkwasser, Oberflächenwasser und Abwasser) fest. Eine geeignete Vorbehaltung der Probe (z.B. Verdünnung) und die Anwendung eines Leitfähigkeitsdetektors (LD) machen die in Tabelle 1 angegebenen Arbeitsbereiche möglich. Die Anwendbarkeit des Verfahrens für Abwasserproben sollten in jedem Fall geprüft werden.

Qualité de l'eau - Dosage par chromatographie ionique, des ions Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+ et Ba2+ dissous - Méthode applicable pour l'eau et les eaux résiduaires (ISO 14911:1998)

La présente Norme internationale spécifie une méthode de dosage des cations Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+ et Ba2+ dissous dans l'eau (par exemple eau potable, eaux de surface, eaux résiduaires).  En faisant subir un prétraitement approprié à l'échantillon (par exemple une dilution) et en utilisant un détecteur conductimétrique (CD), il est possible d'obtenir les gammes de travail données dans le tableau 1.  L'applicabilité de cette méthode pour les échantillons d'eaux résiduaires doit être vérifiée au cas par cas.

Določevanje raztopljenih ionov Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+ in Ba2+ z ionsko kromatografijo - Metoda za vodo in odpadno vodo (ISO 14911:1998)

General Information

Status
Published
Publication Date
17-Aug-1999
Technical Committee
Drafting Committee
Current Stage
9093 - Decision to confirm - Review Enquiry
Due Date
21-May-2008
Completion Date
21-May-2008

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SLOVENSKI STANDARD
SIST EN ISO 14911:2000
01-februar-2000
'RORþHYDQMHUD]WRSOMHQLKLRQRY/L1D1+.0Q&D0J6ULQ
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Water quality - Determination of dissolved Li+, Na+, NH4+, K+, Mn2+, Ca2+, Mg2+, Sr2+

and Ba2+ using ion chromatography - Method for water and waste water (ISO
14911:1998)

Wasserbeschaffenheit - Bestimmung der gelösten Kationen Li+, Na+, NH4+, K+, Mn2+,

Ca2+, Mg2+, Sr2+ und Ba2+ mittels Ionenchromatographie - Verfahren für Wasser und

Abwasser (ISO 14911:1998)

Qualité de l'eau - Dosage par chromatographie ionique, des ions Li+, Na+, NH4+, K+,

Mn2+, Ca2+, Mg2+, Sr2+ et Ba2+ dissous - Méthode applicable pour l'eau et les eaux

résiduaires (ISO 14911:1998)
Ta slovenski standard je istoveten z: EN ISO 14911:1999
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
SIST EN ISO 14911:2000 en

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

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SIST EN ISO 14911:2000
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SIST EN ISO 14911:2000
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SIST EN ISO 14911:2000
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SIST EN ISO 14911:2000
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SIST EN ISO 14911:2000
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SIST EN ISO 14911:2000
INTERNATIONAL ISO
STANDARD 14911
First edition
1998-10-01
Water quality — Determination of dissolved
+ + + + 2+ 2+ 2+ 2+
Li , Na , NH , K , Mn , Ca , Mg , Sr and
Ba using ion chromatography — Method
for water and waste water
+ +
Qualité de l'eau — Dosage, par chromatographie ionique, des ions Li , Na ,
+ + 2+ 2+ 2+ 2+ 2+
NH , K , Mn , Ca , Mg , Sr et Ba dissous — Méthode applicable
pour l'eau et les eaux résiduaires
Reference number
ISO 14911:1998(E)
---------------------- Page: 7 ----------------------
SIST EN ISO 14911:2000
ISO 14911:1998(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.
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.
International Standard ISO 14911 was prepared by Technical Committee
TC 147, Water quality, Subcommittee SC 2, Physical, chemical,
biochemical methods.
Annexes A and B of this International Standard are for information only.
© ISO 1998

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 the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
---------------------- Page: 8 ----------------------
SIST EN ISO 14911:2000
ISO ISO 14911:1998(E)
Introduction
The essential minimum requirements of an ion chromatographic system
applied within the scope of this International Standard are given in
clause 5.
The diversity of the appropriate and suitable assemblies and the procedural
steps depending on them permit a general description only.
Further information on the analytical technique is given in the normative
references (see clause 2) and the bibliography.
iii
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SIST EN ISO 14911:2000
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SIST EN ISO 14911:2000
INTERNATIONAL STANDARD © ISO ISO 14911:1998(E)
+ + + + 2+
Water quality — Determination of dissolved Li , Na , NH , K , Mn ,
2+ 2+ 2+ 2+
Ca , Mg , Sr and Ba using ion chromatography — Method for
water and waste water
1 Scope
+ + + +

This International Standard specifies a method for the determination of the dissolved cations Li , Na , NH , K ,

2+ 2+ 2+ 2+ 2+

Mn , Ca , Mg , Sr and Ba in water (e.g. drinking water, surface water, waste water).

An appropriate pretreatment of the sample (e.g. dilution) and the application of a conductivity detector (CD) make

the working ranges given in table 1 feasible.

The applicability of the method for waste water samples should be proved in each case.

Table 1 — Working ranges of the analytical method
Cation Typical working range with 10 μl loop
mg/l
Lithium 0,01 to 1
Sodium 0,1 to 10
Ammonium 0,1 to 10
Potassium 0,1 to 10
Manganese 0,5 to 50
Calcium 0,5 to 50
Magnesium 0,5 to 50
Strontium 0,5 to 50
Barium 1 to 100

1) The working range is limited by the ion-exchange capacity of the separator column.

If necessary, the sample shall be diluted to meet the working range, or use a 100 μl loop

for lower working ranges.
2 Normative references

The following standards contain provisions which, through reference in this text, constitute provisions of this

International Standard. At the time of publication, the editions indicated were valid. All standards are subject to

revision, and parties to agreements based on this International Standard are encouraged to investigate the

possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain

registers of currently valid International Standards.
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SIST EN ISO 14911:2000
© ISO
ISO 14911:1998(E)

ISO 5667-1:1980, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes.

ISO 5667-2:1991, Water quality — Sampling — Part 2: Guidance on sampling techniques.

ISO 5667-3:1994, Water quality — Sampling — Part 3: Guidance on the preservation and handling of samples.

ISO 6058:1984, Water quality — Determination of calcium content — EDTA titrimetric method.

ISO 6059:1984, Water quality — Determination of the sum of calcium and magnesium — EDTA titrimetric method

ISO 6333:1986, Water quality — Determination of manganese — Formaldoxime spectrometric method.

ISO 7980:1986, Water quality — Determination of calcium and magnesium — Atomic absorption spectrometric

method.

ISO 8466-1:1990, Water quality — Calibration and evaluation of analytical methods and estimation of performance

characteristics — Part 1: Statistical evaluation of the linear calibration function.

ISO 8466-2:1993, Water quality — Calibration and evaluation of analytical methods and estimation of performance

characteristics — Part 2: Calibration strategy for non-linear second order calibration functions.

3 Interferences

3.1 Organics such as amino acids and aliphatic amines can interfere with the determination of inorganic cations.

3.2 If a strong complexing agent such as pyridine-2,6-dicarboxylic acid (PDA) is not present in the mobile phase,

2+ 2+ 2+

and if the suppressor technique is not used, cross interferences from other cations like Zn , Ni , Cd etc. can

occur.

3.3 Cross-sensitivities with other cations, e.g. manganese, are dependent on the selectivity of the separator

column used. If the quality requirements in clause 8 are not achieved, the sample shall be diluted.

+ +

3.4 Cross-sensitivities in the determination of NH and Na can occur when there are large differences in

concentration.

3.5 Solid material and organic compounds (such as mineral oils, detergents and humic acids) shorten the lifetime

of the separator column. They are therefore eliminated from the sample (9.3).
4 Principle
+ + + + 2+ 2+ 2+ 2+ 2+

Liquid chromatographic separation of Li , Na , NH , K , Mn , Ca , Mg , Sr and Ba by means of a separator

column. A low-capacity cation exchanger is used as the stationary phase, and usually, aqueous solutions of mono-

and dibasic acids as mobile phases (eluent, see 6.16).

These cations are detected by conductivity. It is essential that the eluents have a sufficiently low conductivity. For

this reason, a conductivity detector (CD) is often combined with a suppressor device (e.g. an anion exchanger)

which will reduce the conductivity of the eluent and transform the separated cations into their corresponding bases.

In the conductivity detection without chemical suppression, the difference between the ion equivalent conductivities

is measured directly after the column. This difference should be as high as possible and the detector cell

temperature should be stabilized within ± 0,1 °C.

The concentration of the respective cations is determined by a calibration of the overall procedure. Particular cases

can require calibration by means of standard addition (spiking).
---------------------- Page: 12 ----------------------
SIST EN ISO 14911:2000
© ISO
ISO 14911:1998(E)
5 Essential minimum requirements

The essential minimum requirements of an ion chromatographic system applied within the scope of this

International Standard are the following:

a) Resolution power (R) of the column: For the cation to be determined it is essential that the peak

resolution does not fall below R = 1,3 (see clause 8, figure 3).

b) Method of detection: Measurement of the electrical conductivity with or without

suppressor device.
c) Applicability of the method: Working ranges according to table 1.

d) Calibration (10.2): Calibration and determination of the linear (see ISO 8466-1) or

quadratic (see ISO 8466-2) working range. Use of the method
of standard addition to special cases of application (see 10.3).

e) Guaranteeing the analytical quality (10.3.2): Validity check of the calibration function. Replicate

determinations, if necessary.
6 Reagents

Use only reagents of recognized analytical grade. Carry out weighing with an accuracy of ±1 % of the nominal

mass. The water shall have an electrical conductivity of < 0,01 mS/m and shall not contain particulate matter of a

particle size > 0,45 μm.
6.1 DL-2,3-Diaminopropionic acid monohydrochloride (DAP), C H N O �HCI.
3 8 2 2
6.2 Hydrochloric acid solution, c(HCl) = 7,7 mol/l.
6.3 Methanesulfonic acid, CH O S (≥ 99%).
4 3
6.4 Pyridine 2,6-dicarboxylic acid (PDA), C H NO
7 5 4
6.5 Tartaric acid, C H O
4 6 6
6.6 Nitric acid solution, c(HNO = 1 mol/l.
6.7 Lithium nitrate, LiNO .
6.8 Sodium nitrate, NaNO .
6.9 Ammonium chloride, NH Cl.
6.10 Potassium nitrate, KNO .
6.11 Manganese nitrate tetrahydrate, Mn(NO ) �4H O.
3 2 2
6.12 Calcium nitrate tetrahydrate, Ca(NO ) �4H O.
3 2 2
6.13 Magnesium nitrate hexahydrate, Mg(NO ) �6H O.
3 2 2
6.14 Strontium nitrate, Sr(NO )
3 2
6.15 Barium nitrate, Ba(NO )
3 2
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SIST EN ISO 14911:2000
© ISO
ISO 14911:1998(E)

6.16 Eluents, their choice depending on the type of separator column and detector.

Follow the column manufacturer´s instructions for the exact composition of the eluent. The eluent compositions

described in 6.16.1.1, 6.16.1.2, 6.16.2.1.1 and 6.16.2.2 are examples only.
A selection of reagents for preparing common eluents is presented in 6.1 to 6.6.

Degas all eluents or prepare eluents using degassed water. Avoid any renewed gas pick-up during operation (e.g.

by helium sparging). Store the eluents in the dark and renew as required.

6.16.1 Examples of eluents for ion chromatography using the suppressor technique

For the application of the suppressor technique, solutions containing strong acids like hydrochloric acid or

methanesulfonic acid or mixtures of these acids with DAP (6.1) can be used. Eluent concentrates are not

recommended, but can be used.
6.16.1.1 Hydrochloric acid / DAP eluent
+ + + + 2+ 2+ 2+ 2+ 2+

The following eluent is applicable for the determination of Li , Na , NH , K , Mn , Ca , Mg , Sr and Ba :

Place 5,2 ml of a hydrochloric acid solution (6.2) and 0,562 g ± 0,006 g of DAP (6.1) into a 1000 ml volumetric flask

and dilute to volume with degassed water.

The solution contains 0,04 mol/l of hydrochloric acid and 0,004 mol/l DAP (6.1). Store the solution at 4 °C to 6 °C,

renew it every 7 d.
6.16.1.2 Methanesulfonic acid eluent
+ + + + 2+ 2+ 2+ 2+ 2+

The following eluent is applicable for the determination of Li , Na , NH , K , Mn , Ca , Mg , Sr and Ba :

Place 1,3 ml of methanesulfonic acid-solution (6.3) into a 1000 ml volumetric flask and dilute to volume with

degassed water.

The solution contains 0,02 mol/l of methanesulfonic acid. Renew the eluent every 3 d.

6.16.2 Examples of eluents for ion chromatography without using the suppressor technique

For ion chromatography techniques without suppressor devices, acids like nitric, tartaric, oxalic etc. are used. The

solutions can contain various additions, e.g. alcohols. The concentration of the acids is usually in the range of

0,001 mol/l to 0,01 mol/l. Concentrate and eluent solutions are prepared as described in 6.16.

6.16.2.1 Tartaric acid/PDA concentrate

The eluent concentrate has proved to be successful for the eluent preparation (6.16.2.1.1):

Place 1,671 g ± 0,017 g of PDA (6.4) in a beaker of capacity 1000 ml, add approximately 500 ml of water (clause 6).

Stir and dissolve by heating (60 °C to 80 °C). After cooling add 6,003 g ± 0,060 g tartaric acid (6.5) and transfer the

cool solution into a 1000 ml volumetric flask and dilute to volume with water.

The solution contains 0,01 mol/l PDA and 0,04 mol/l tartaric acid and is stable for one month if stored at 4 °C to

6 °C.
6.16.2.1.1 Tartaric acid/PDA eluent
+ + + + 2+ 2+ 2+ 2+ 2+

For the determination of Li , Na , NH , K , Mn , Ca , Mg , Sr and Ba , the following eluent has proved to be

successful:

Place 100 ml of the concentrate (6.16.2.1) into a 1000 ml volumetric flask and dilute to volume with water (clause 6).

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SIST EN ISO 14911:2000
© ISO
ISO 14911:1998(E)

The solution contains 0,001 mol/l PDA and 0,004 mol/l tartaric acid. The eluent pH is 2,8. Renew the eluent every

3 d.
6.16.2.2 Nitric acid eluent
+ + + + 2+ 2+ 2+ 2+ 2+

For the determination of Li , Na , NH , K , Mn , Ca , Mg , Sr and Ba , the following eluent has proved to be

successful:

Place 500 ml of water (clause 6) into a 1000 ml volumetric flask, add 20 ml of the nitric acid solution (6.6) and dilute

to volume with water.
The solution contains 0,02 mol/l nitric acid. Renew the eluent every 3 d.
6.17 Stock solutions
+ + + + 2+ 2+

Prepare stock solutions of concentration r = 1000 mg/l for each of the cations Li , Na , NH , K , Mn , Ca ,

2+ 2+ 2+
Mg , Sr and Ba :

Dissolve the appropriate mass of each of the substances, prepared as stated in table 2, in approximately 800 ml of

water (clause 6, degassed with nitrogen or helium), in 1000 ml volumetric flasks of polyethylene, add 1 ml nitric acid

solution (6.6). Dilute to volume with water. The solutions are stable for six months if stored at 4 °C to 6 °C in

polyethylene bottles.
Table 2 — Mass of portion and suggestions how to store stock solutions
Cation Concentration Pretreatment Storage at 4 °C to 6 °C
Salt
derived from
in polyethylene bottles
substance-portion
g/l
Lithium LiNO 9,933 7 ± 0,099 Dry at 105°C ± 5 °C,
in 0,001 mol/l HNO
2 h
Sodium NaNO 3,697 9 ± 0,037 Dry at 105°C ± 5 °C in water
Ammonium NH Cl 2,965 5 ± 0,030 Dry at 105°C± 5 °C in water
Potassium KNO 2,586 0 ± 0,026 Dry at 105°C ± 5 °C in water
3) 2)
Manganese Mn(NO ) { 4 H O Dry in a desiccator
3 2 2 4,569 0 ± 0,046 in 0,001 mol/l HNO
3) 2)
Calcium Ca(NO ) { 4 H O Dry in a desiccator
3 2 2 5,892 0 ± 0,059 in 0,001 mol/l HNO
3) 2)
Magnesium Mg(NO ) { 6 H O Dry in a desiccator
3 2 2 10,549 7 ± 0,105 in 0,001 mol/l HNO
Strontium Sr(NO ) 2,415 3 ± 0,024 Dry at 105°C ± 5 °C
in 0,001 mol/l HNO
3 2
Barium Ba(NO ) 1,903 1 ± 0,019 Dry at 105°C ± 5 °C
in 0,001 mol/l HNO
3 2

1) Alternatively, use commercially available solutions of the respective cation and nitric acid concentrations.

2) Check the content of analyte before use.

3) Titre adjustment is neccessary prior to use (for Mn: in accordance with ISO 6333; for Ca/Mg: in accordance with ISO 7980 or

ISO 6058/ISO 6059).
6.18 Mixed standard solutions

Depending upon the concentrations expected, prepare standard solutions of different cation composition and

concentration from the stock solutions (6.17). The risk of changes in concentration caused by interaction with the

vessel material increases with decreasing cation concentration. The lower the sodium and potassium concentration

in the standard solution, the higher the probability of a change in concentration due to an interaction with the vessel

material. Store the standard solutions in polyethylene vessels.
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SIST EN ISO 14911:2000
© ISO
ISO 14911:1998(E)
+ + + + 2+ 2+ 2+ 2+ 2+
6.18.1 Mixed standard solution of Li , Na , NH , K , Mn , Ca , Mg , Sr and Ba

The mass concentrations of the solutions are given in table 3. If only some of the cations listed in tables 3 and 4

have to be determined, the following steps are applicable for those cations only.

Place in a 100 ml polyethylene volumetric flask approximately 50 ml of water (clause 6), add 1 ml nitric acid solution

(6.6), and pipette the volume of each of the substances as stated in table 3, and fill up to volume with water

(clause 6). Store the solution in a polyethylene vessel. If stored at 2 °C to 6 °C, the solution is stable for one week.

Table 3 — Volumes of stock solutions for the preparation of the mixed standard solution

Cation Stock solution Cation concentration
ml mg/l
0,5 5
1,0 10
1,0 10
2,0 20
2,0 20
2,0 20
2,0 20
5,0 50
10,0 100

Other mixed standard solutions can be made by respective dilutions of the mixed standard solution.

6.19 Cation calibration solutions

Depending on the cation concentration expected, use the stock solutions or the mixed standard solutions (6.17 or

6.18.1) to prepare 5 to 10 calibration solutions distributed over the expected working range as equally as possible.

For example, proceed as follows for the ranges:
a) 0,05 mg/l to 0,5 mg/l Li
+ +
b) 0,1 mg/l to 1,0 mg/l Na , NH
+ 2+ 2+ 2+
c) 0,2 mg/l to 2,0 mg/l K , Mn , Ca , Mg
d) 0,5 mg/l to 5,0 mg/l Sr
e) 1,0 mg/l to 10,0 mg/l Ba

Pipette into a series of 100 ml polyethylene volumetric flasks a volume of 1 ml, 2 ml, 3 ml, 4 ml, 5 ml, 6 ml, 7 ml,

8 ml, 9 ml and 10 ml of the mixed standard solution (6.18.1), add 0,1 ml nitric acid solution (6.6) and dilute to volume

with water (clause 6).

The concentrations of the calibration solutions are listed in table 4. Prepare the calibration solutions on the day of

use.
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SIST EN ISO 14911:2000
© ISO
ISO 14911:1998(E)
Table 4 — Concentrations of the calibration solutions
Cation Concentrations of the calibration solutions
mg/l
0,05; 0,1; 0,15; 0,2; 0,25; 0,3; 0,35; 0,4; 0,45; 0,50
0,1; 0,2; 0,3; 0,4; 0,5; 0,6; 0,7; 0,8; 0,9; 1,0
0,1; 0,2; 0,3; 0,4; 0,5; 0,6; 0,7; 0,8; 0,9; 1,0
+ 0,2; 0,4; 0,6; 0,8; 1,0; 1,2; 1,4; 1,6; 1,8; 2,0
0,2; 0,4; 0,6; 0,8; 1,0; 1,2; 1,4; 1,6; 1,8; 2,0
0,2; 0,4; 0,6; 0,8; 1,0; 1,2; 1,4; 1,6; 1,8; 2,0
0,2; 0,4; 0,6; 0,8; 1,0; 1,2; 1,4; 1,6; 1,8; 2,0
0,5; 1,0; 1,5; 2,0; 2,5; 3,0; 3,5; 4,0; 4,5; 5,0
1,0; 2,0;
...

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