ISO 4940:2025
(Main)Steel and cast iron — Determination of nickel content — Flame atomic absorption spectrometric method
Steel and cast iron — Determination of nickel content — Flame atomic absorption spectrometric method
This document specifies a flame atomic absorption spectrometric method (FAAS) for the determination of nickel content in steel and cast iron. The method is applicable to nickel contents in the range of 0,002 % (mass fraction) to 0,5 % (mass fraction).
Aciers et fontes — Détermination de la teneur en nickel — Méthode par spectrométrie d'absorption atomique dans la flamme
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International
Standard
ISO 4940
Second edition
Steel and cast iron — Determination
2025-07
of nickel content — Flame atomic
absorption spectrometric method
Aciers et fontes — Détermination de la teneur en nickel —
Méthode par spectrométrie d'absorption atomique dans la flamme
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 2
6 Apparatus . 3
7 Sampling and sample preparation . 4
8 Procedure . 4
8.1 General .4
8.2 Test portion .4
8.3 Blank test .4
8.4 Determination .4
8.4.1 Preparation of the test solution .4
8.4.2 Nickel contents higher than 0,10 % .5
8.4.3 Preparation of the calibration solutions .5
8.4.4 Adjustment of the atomic absorption spectrometer .6
8.4.5 Spectrometric measurements .6
8.5 Plotting the calibration curve .7
8.6 Use of bracketing method .7
9 Expression of results . 7
9.1 Use of the calibration curve .7
9.2 Use of bracketing method .8
10 Test report . 8
Annex A (informative) Precision . 9
Annex B (informative) Procedures for the determination of instrumental criteria .11
Bibliography .13
iii
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 document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of
determination of chemical composition.
This second edition cancels and replaces the first edition (ISO 4940:1985), which has been technically
revised.
The main changes are as follows:
— the normative references have been updated;
— some notes that can contribute to a better accuracy of the method like preparation of the iron base
solution and the test solution have been added;
— a Bibliography has been added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
International Standard ISO 4940:2025(en)
Steel and cast iron — Determination of nickel content —
Flame atomic absorption spectrometric method
1 Scope
This document specifies a flame atomic absorption spectrometric method (FAAS) for the determination of
nickel content in steel and cast iron.
The method is applicable to nickel contents in the range of 0,002 % (mass fraction) to 0,5 % (mass fraction).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical composition
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
Dissolution of a test portion in a mixture of appropriate acids followed by evaporation to fuming with
perchloric acid.
Nebulization of the test solution into an air/acetylene flame of an atomic absorption spectrometer.
Spectrometric measurement of the atomic absorption of the 232,0 nm or 352,5 nm spectral line emitted by a
nickel hollow cathode lamp.
With some instruments it is not possible to obtain sufficient sensitivity at the wavelength of 352,5 nm for
low concentrations of nickel near the bottom end of the application range and in such cases the alternative
wavelength of 232,0 nm shall be used.
At the wavelength of 352,5 nm, the signal-to-noise ratio is higher than at the wavelength of 232,0 nm. In
general, the use of the 352,5 nm line will give better reproducibility.
NOTE Other suitable radiation sources can also be used, provided the criteria in 6.1.1 to 6.1.4 are still met.
In Annex A, the composition of the test samples used in the precision test is given in Table A.1, and the
related results are given in Table A.2.
The procedures for the determination of instrumental criteria is given in Annex B.
5 Reagents
Unless otherwise stated, use only reagents of recognized analytical grade and only grade 2 water as
specified in ISO 3696.
5.1 Pure iron, nickel content less than 0,000 5 % (mass fraction).
5.2 Hydrochloric-nitric acids mixture.
Mix three volumes of hydrochloric acid (ρ approximately 1,19 g/ml), one volume of nitric acid (ρ
approximately 1,40 g/ml) and two volumes of water.
This mixture shall be prepared immediately before use.
5.3 Nitric-perchloric acids mixture.
Mix 100 ml of nitric acid (ρ approximately 1,40 g/ml) with 800 ml of perchloric acid (ρ approximately
1,54 g/ml). Dilute to 1 000 ml with water and mix.
Perchloric acid (ρ approximately 1,67 g/ml) can also be used. 100 ml of perchloric acid (ρ approximately
1,54 g/ml) are equivalent to 79 ml of perchloric acid (ρ approximately 1,67 g/ml).
5.4 Nickel standard solution, 1 g/l.
Weigh, to the nearest 0,001 g, 0,500 g of high purity nickel [Ni ≥ 99,9 % (mass fraction)] and transfer into a
heat-resistant glassware of suitable size. Add 25 ml of nitric acid (ρ approximately 1,40 g/ml, diluted 1 + 1).
Cover with a watch glass, and, heat gently to assist dissolution. When dissolution is complete, boil to remove
nitrogen oxides. Allow to cool to room temperature and transfer the solution quantitatively into a 500 ml
one-mark volumetric flask. Dilute to the mark with water and mix.
1 ml of this solution contains 1,0 mg of nickel.
5.5 Nickel standard solution, 0,04 g/l.
Transfer 10,0 ml of nickel standard solution (5.4) into a 250 ml one-mark volumetric flask. Dilute to the
mark with water and mix.
1 ml of this solution contains 0,04 mg of nickel.
Prepare this solution immediately prior to use.
5.6 Iron base solution, 40 g/l.
Weigh, to the nearest 0,01 g, 10,00 g of pure iron (5.1) and transfer into an 800 ml beaker. Add 100 ml of the
hydrochloric-nitric acids mixture (5.2), cover the beaker with a watch glass and heat gently until the iron is
dissolved.
When dissolution is complete, add 150 ml of the nitric-perchloric acids mixture (5.3) and heat until dense
white fumes of perchloric acid appear. Continue heating for 1 min and allow to cool.
In order to get a better mastery of the acidity (volume of free perchloric acid) of the sample solutions and of
the calibration solutions, perchloric fumes may be maintained until iron crystallizes.
Add 100 ml of water and heat gently to dissolve the salts. Cool again and transfer the solution quantitatively
into a 250 ml one-mark volume
...
FINAL DRAFT
International
Standard
ISO/FDIS 4940
ISO/TC 17/SC 1
Steel and cast iron — Determination
Secretariat: JISC
of nickel content — Flame atomic
Voting begins on:
absorption spectrometric method
2025-05-09
Aciers et fontes — Détermination de la teneur en nickel —
Voting terminates on:
Méthode par spectrométrie d'absorption atomique dans la
2025-07-04
flamme
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/FDIS 4940:2025(en) © ISO 2025
FINAL DRAFT
ISO/FDIS 4940:2025(en)
International
Standard
ISO/FDIS 4940
ISO/TC 17/SC 1
Steel and cast iron — Determination
Secretariat: JISC
of nickel content — Flame atomic
Voting begins on:
absorption spectrometric method
Aciers et fontes — Détermination de la teneur en nickel —
Voting terminates on:
Méthode par spectrométrie d'absorption atomique dans la flamme
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland Reference number
ISO/FDIS 4940:2025(en) © ISO 2025
ii
ISO/FDIS 4940:2025(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 2
6 Apparatus . 3
7 Sampling and sample preparation . 4
8 Procedure . 4
8.1 General .4
8.2 Test portion .4
8.3 Blank test .4
8.4 Determination .4
8.4.1 Preparation of the test solution .4
8.4.2 Nickel contents higher than 0,10 % .5
8.4.3 Preparation of the calibration solutions .5
8.4.4 Adjustment of the atomic absorption spectrometer .6
8.4.5 Spectrometric measurements .6
8.5 Plotting the calibration curve .7
8.6 Use of bracketing method .7
9 Expression of results . 7
9.1 Use of the calibration curve .7
9.2 Use of bracketing method .8
10 Test report . 8
Annex A (informative) Precision . 9
Annex B (informative) Procedures for the determination of instrumental criteria .11
Bibliography .13
iii
ISO/FDIS 4940:2025(en)
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 document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of
determination of chemical composition.
This second edition cancels and replaces the first edition (ISO 4940:1985), which has been technically
revised.
The main changes are as follows:
— the normative references have been updated;
— some notes that can contribute to a better accuracy of the method like preparation of iron and the test
solution have been added;
— a Bibliography has been added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
FINAL DRAFT International Standard ISO/FDIS 4940:2025(en)
Steel and cast iron — Determination of nickel content —
Flame atomic absorption spectrometric method
1 Scope
This document specifies a flame atomic absorption spectrometric method (FAAS) for the determination of
nickel content in steel and cast iron.
The method is applicable to nickel contents in the range of 0,002 % (mass fraction) to 0,5 % (mass fraction).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical composition
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
Dissolution of a test portion in a mixture of appropriate acids followed by evaporation to fuming with
perchloric acid.
Nebulization of the test solution into an air/acetylene flame of an atomic absorption spectrometer.
Spectrometric measurement of the atomic absorption of the 232,0 nm or 352,5 nm spectral line emitted by a
nickel hollow cathode lamp.
With some instruments it is not possible to obtain sufficient sensitivity at the wavelength of 352,5 nm for
low concentrations of nickel near the bottom end of the application range and in such cases the alternative
wavelength of 232,0 nm shall be used.
At the wavelength of 352,5 nm, the signal-to-noise ratio is higher than at the wavelength of 232,0 nm. In
general, the use of the 352,5 nm line will give better reproducibility.
NOTE Other suitable radiation sources can also be used, provided the criteria in 6.1.1 to 6.1.4 are still met.
ISO/FDIS 4940:2025(en)
The composition of test sample used is given in Annex A, and the procedures for the determination of
instrumental criteria is given in Annex B.
5 Reagents
Unless otherwise stated, use only reagents of recognized analytical grade and only grade 2 water as
specified in ISO 3696.
5.1 Pure iron, nickel content less than 0,000 5 % (mass fraction).
5.2 Hydrochloric-nitric acids mixture.
Mix three volumes of hydrochloric acid (ρ approximately 1,19 g/ml), one volume of nitric acid (ρ
approximately 1,40 g/ml) and two volumes of water.
This mixture shall be prepared immediately before use.
5.3 Nitric-perchloric acids mixture.
Mix 100 ml of nitric acid (ρ approximately 1,40 g/ml) with 800 ml of perchloric acid (ρ approximately 1,54 g/
ml). Dilute to 1 000 ml with water and mix.
Perchloric acid (ρ approximately 1,67 g/ml) can also be used. 100 ml of perchloric acid (ρ approximately
1,54 g/ml) are equivalent to 79 ml of perchloric acid (ρ approximately 1,67 g/ml).
5.4 Nickel standard solution, 1 g/l.
Weigh, to the nearest 0,001 g, 0,500 g of high purity nickel [Ni ≥ 99,9 % (mass fraction)] and transfer into a
heat-resistant glassware of suitable size. Add 25 ml of nitric acid (ρ approximately 1,40 g/ml, diluted 1 + 1).
Cover with a
...
2025-05-30
ISO/DISFDIS 4940:2025(en)
ISO /TC 17/SC 1/WG #
Secretariat: JISC
Date: 2025-04-25
Steel and cast iron — Determination of nickel content — Flame
atomic absorption spectrometric method
Aciers et fontes – — Détermination de la teneur en nickel –— Méthode par spectrométrie d'absorption
atomique dans la flamme
FDIS stage
ISO /FDIS 4940:2024(X2025(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: copyright@iso.org
Website: www.iso.orgwww.iso.org
Published in Switzerland
ii © ISO #### 2025 – All rights reserved
ii
ISO/DISFDIS 4940:2025(en)
Contents
Foreword . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 2
6 Apparatus . 3
7 Sampling and sample preparation . 4
8 Procedure . 4
9 Expression of results . 8
10 Test report . 9
Annex A (informative) Precision . 10
Annex B (informative) Procedures for the determination of instrumental criteria . 12
Bibliography . 14
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 2
6 Apparatus . 2
6.1 Atomic absorption spectrometer . 3
6.1.1 Minimum precision . 3
6.1.2 Limit of detection . 3
6.1.3 Calibration linearity. 3
6.1.4 Characteristic concentration . 3
6.2 Ancillary equipment . 3
7 Sampling and sample preparation . 4
8 Procedure . 4
8.1 Test portion . 4
8.2 Blank test . 4
8.3 Determination . 4
8.3.1 Preparation of the test solution . 4
8.3.2 Preparation of the calibration solutions . 5
8.3.3 Adjustment of the atomic absorption spectrometer . 6
8.3.4 Spectrometric measurements . 6
8.4 Plotting the calibration curve . 6
8.5 Use of bracketing method . 7
9 Expression of results . 7
9.1 Use of the calibration curve . 7
iii
ISO /FDIS 4940:2024(X2025(en)
9.2 Use of bracketing method . 7
10 Test report . 8
Annex A (informative) Precision . 9
A.1 General . 9
A.2 Repeatability . 9
A.3 Reproducibility . 9
Annex B (informative) Procedures for the determination of instrumental criteria . 11
B.1 Determination of minimum precision . 11
B.2 Determination of limit of detection, ρ . 11
Ni,min
B.3 Criterion for graph linearity . 12
B.4 Determination of characteristic concentration ρ . 12
Ni,K
Bibliography . 13
iv © ISO #### 2025 – All rights reserved
iv
ISO/DISFDIS 4940:2025(en)
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 document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents.www.iso.org/patents. ISO shall not be held responsible for identifying any or all such
patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of
determination of chemical composition.
This second edition cancels and replaces the first edition (ISO 4940:1985), which has been technically revised.
The main changes are as follows:
— — the normative references have been revisedupdated;
— — some notes that can contribute to a better accuracy of the method like preparation of iron and the test
solution have been added;
— — a Bibliography has been added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
ISO/FDIS 4940:2025(en)
Steel and cast iron — Determination of nickel content — Flame atomic
absorption spectrometric method
1 Scope
This document specifies a flame atomic absorption spectrometric method (FAAS) for the determination of
nickel content in steel and cast iron.
The method is applicable to nickel contents in the range of 0,002 % (mass fraction) to 0,5 % (mass fraction).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical composition
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
4 Principle
Dissolution of a test portion in a mixture of appropriate acids followed by evaporation to fuming with
perchloric acid.
Nebulization of the test solution into an air/acetylene flame of an atomic absorption spectrometer.
Spectrometric measurement of the atomic absorption of the 232,0 nm or 352,5 nm spectral line emitted by a
nickel hollow cathode lamp.
With some instruments it is not possible to obtain suffic
...
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