SIST EN 10179:2024
(Main)Steels - Determination of nitrogen (trace amounts) - Spectrophotometric method
Steels - Determination of nitrogen (trace amounts) - Spectrophotometric method
This document specifies a spectrophotometric method for the determination of nitrogen in steels.
The method is primarily intended for the determination of total nitrogen in very low contents in non-alloy steels.
It can be used, however, for any low nitrogen ferrous alloy that is soluble in hydrochloric acid provided that the acid-resistant form of silicon nitride is not present. This highly resistant nitride has been found only in samples of silicon steels manufactured without aluminium addition and then only in sheet material.
The method is applicable to nitrogen contents from 0.000 5 % (by mass) to 0.005 % (by mass).
Stähle - Bestimmung von Stickstoff (Spurengehalte) - Photometrisches Verfahren
Dieses Dokument legt ein spektralphotometrisches Verfahren zur Bestimmung von Stickstoff in Stählen fest.
Das Verfahren ist in erster Linie für die Bestimmung von Gesamtstickstoff in sehr geringen Gehalten in nicht legierten Stählen bestimmt. Es kann jedoch für jede Eisenlegierung mit niedrigem Stickstoffgehalt angewendet werden, die in Salzsäure löslich ist, vorausgesetzt, dass die säurebeständige Form des Siliziumnitrids nicht vorhanden ist.
Dieses hochresistente Nitrid wurde nur in Proben von Siliziumstählen gefunden, die ohne Aluminiumzusatz hergestellt wurden, und dann auch nur in Blechmaterial.
Das Verfahren ist für Stickstoffgehalte von 0,000 5 % (Masse) bis 0,005 % (Masse) anwendbar.
Aciers - Détermination de l'azote (à l'état de traces) - Méthode spectrophotométrique
Le présent document spécifie une méthode de détermination spectrophotométrique de l'azote dans les aciers.
La méthode est principalement destinée à la détermination de l'azote total en très faible teneur dans les aciers non alliés.
Elle peut toutefois être utilisée pour tout alliage ferreux à bas azote soluble dans l'acide chlorhydrique, pourvu que celui-ci ne contienne pas de nitrures de silicium résistant à l'acide. Ces nitrures très résistants n'ont jusqu'alors été trouvés que dans des échantillons d'aciers au silicium produits sans addition d'aluminium, et donc uniquement dans les tôles.
La méthode est applicable aux aciers, dont les teneurs en azote sont comprises entre 0.000 5 % (en masse) et 0.005 % (en masse).
Jekla - Določevanje dušika (v sledeh) v jeklih - Spektrofotometrična metoda
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2024
Jekla - Določevanje dušika (v sledeh) v jeklih - Spektrofotometrična metoda
Steels - Determination of nitrogen (trace amounts) - Spectrophotometric method
Stähle - Bestimmung von Stickstoff (Spurengehalte) - Photometrisches Verfahren
Aciers - Détermination de l'azote (à l'état de traces) - Méthode spectrophotométrique
Ta slovenski standard je istoveten z: EN 10179:2024
ICS:
77.040.30 Kemijska analiza kovin Chemical analysis of metals
77.080.20 Jekla Steels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 10179
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2024
EUROPÄISCHE NORM
ICS 77.040.30 Supersedes EN 10179:1989
English Version
Steels - Determination of nitrogen (trace amounts) -
Spectrophotometric method
Aciers - Détermination de l'azote (à l'état de traces) - Stähle - Bestimmung von Stickstoff (Spurengehalte) -
Méthode spectrophotométrique Photometrisches Verfahren
This European Standard was approved by CEN on 29 April 2024.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 10179:2024 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 4
6 Apparatus . 7
7 Sampling . 12
8 Procedure . 12
8.1 Test portion . 12
8.2 Blank test . 12
8.3 Preparation of the steam distillation apparatus . 12
8.4 Determination . 13
8.4.1 Preparation of the test solution . 13
8.4.2 Distillation . 13
8.4.3 Development of the colour . 13
8.4.4 Spectrophotometric measurements . 14
8.5 Establishment of the calibration curve . 14
8.5.1 Preparation of the calibration solutions . 14
8.5.2 Spectrophotometric measurements . 14
8.5.3 Plotting the calibration curve . 15
9 Expression of results . 15
10 Test report . 15
Annex A (informative) Precision data . 16
Bibliography . 17
European foreword
This document (EN 10179:2024) has been prepared by Technical Committee CEN/TC 459/SC 2
“Methods of chemical analysis for iron and steel”, the secretariat of which is held by SIS.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by December 2024, and conflicting national standards
shall be withdrawn at the latest by December 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 10179:1989.
In comparison with the previous edition, the following technical modifications have been made:
— normative references: updated;
— Clause 3; Terms and definitions: added;
— references 5.10, 5.11, 5.14, 5.17 and 5.18: added;
— Clause 10: updated;
— Bibliography: added.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye
and the United Kingdom.
1 Scope
This document specifies a spectrophotometric method for the determination of nitrogen in steels.
The method is primarily intended for the determination of total nitrogen in very low contents in non-
alloy steels.
It can be used, however, for any low nitrogen ferrous alloy that is soluble in hydrochloric acid provided
that the acid-resistant form of silicon nitride is not present. These highly resistant nitrides have been
found only in samples of silicon steels manufactured without aluminium addition and then only in
sheet material.
The method is applicable to nitrogen contents from 0,000 5 % (by mass) to 0,005 % (by mass).
The precision data of the present method are given in Annex A.
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.
EN ISO 648, Laboratory glassware — Single-volume pipettes (ISO 648)
EN ISO 1042, Laboratory glassware — One-mark volumetric flasks (ISO 1042)
EN ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical
composition (ISO 14284)
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological 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 the test portion with hydrochloric acid and separation of the acid-insoluble residue by
centrifugation.
Decomposition of the acid-insoluble residue by intense fuming with sulphuric acid and addition of the
extract to the solution of the test portion containing the acid-soluble nitrogen.
Recovery of the total nitrogen as ammonia by steam distillation over sodium hydroxide.
Spectrophotometric measurement of the coloured complex produced by a reaction with indophenol
blue.
5 Reagents
During the analysis use only reagents of recognized analytical grade and which are known to give a
very low nitrogen bank. The same batch of each reagent shall be used for every test solution and blank
determination in a given series of analysis.
All references to “water” relate to ammonia-free water. Ammonia-free water shall be prepared by
passing distilled water through a cation exchange column (6.2). It is essential that the resin column
+
shall be acid washed before use to ensure its conversion to the hydrogen form, H . This is most
conveniently done by passing 2 l of a solution of hydrochloric acid (5.2), diluted 1 + 9, through the
column and then washing with water until freed from acid.
5.1 High purity iron or steel with a very low nitrogen content
High purity iron powder or very low nitrogen content mild steel [<0,001 % (by mass) nitrogen] may
be used for this purpose. It should be cleaned in the same way as the sample.
5.2 Hydrochloric acid, ρ 1,19 g/ml approximately
5.3 Sulphuric acid, ρ 1,84 g/ml approximately
Sulphuric acid supplied shall be tested individually and selected for a low content of combined
nitrogen in any form (less than 0,5 µg/g). Nitrogen as ammonia will usually be the major source of
contamination and this may be tested by normal methods, but nitrates may also be present and should
be detected by using the method described below.
Add 6 ml of sulphuric acid (5.3) to 2 ml of water and cool to 60 °C. Add one drop of hydrochloric
acid (5.2) and one drop of diphenylamine (5.8). No blue colour should appear.
NOTE Less than 0,1 µg/g can be detected by this test.
5.4 Sulphuric acid, solution 1 + 4
Carefully add 40 ml of sulphuric acid (5.3) to 160 ml of water.
Allow to cool and mix.
5.5 Sodium hydroxide, 400 g/l
Dissolve 400 g of sodium hydroxide in water, dilute to 1 000 ml and mix.
This solution should be prepared in a polyethylene beaker (water-cooled if necessary) and stored in a
polyethylene bottle.
5.6 Barium chloride, 100 g/l
Dissolve 100 g of barium chloride (BaCl · 2H 0) in water, dilute to 1 000 ml and mix.
2 2
5.7 Chromic-sulphuric acid
Dissolve 2 g of chromium trioxide (CrO ) in 50 ml of water and slowly add 100 ml of sulphuric
acid (5.3) with constant stirring.
5.8 Diphenylamine, 1 g/l
To 25 ml of water, whilst stirring, cautiously add 75 ml of sulphuric acid (5.3) then add 0,1 g of
diphenylamine, stir until dissolved and allow to cool.
5.9 Phenol, 50 g/l
Dissolve 50 g of phenol in water, transfer into a 1 000 ml volumetric flask, dilute to the mark with
water and mix.
Store this solution out of direct sunlight in an amber coloured bottle.
5.10 Potassium iodide (KI)
5.11 Glacial acetic acid, ρ 1,05 g/ml approximately
5.12 Sodium hydroxide - sodium hypochlorite solution
5.12.1 Determination of chlorine in commercial sodium hypochlorite solution
Transfer 10 ml of the sodium hypochlorite solution to be tested into a 250 ml volumetric flask, dilute
to the mark with water and mix.
Transfer, 10 ml of this solution into a 100 ml conical beaker, add 2 g of potassium iodide (5.10) and
10 ml of glacial acetic acid (5.11). Titrate the liberated iodine using sodium thiosulphate (5.15) until
the colour has almost disappeared. Add 2 ml of starch solution (5.16) and continue the titration until
the blue colour has disappeared.
The chlorine content (w ) in per cent (m/v) is given by Formula (1):
Cl
w = 0,886 × V (1)
Cl 1
where
V is the volume in millilitres of sodium thiosulphate (5.15) used in the titration.
5.12.2 Calculation
The volume, V , expressed in millilitres, of sodium hypochlorite solution necessary for the preparation
of 1 l of sodium hydroxide - sodium hypochlorite solution (5.12) is given by Formula (2):
2,1××100 70,,91 225 7
V (2)
0,,886××V 74 44 V
1 1
This volume is equivalent to 2,1 g of chlorine.
5.12.3 Preparation of the solution 5.12
Dissolve 25 g of sodium hydroxide in about 400 ml of water. Exactly add the calculated volume of
sodium hypochlorite solution (5.12.2), dilute t
...
SLOVENSKI STANDARD
oSIST prEN 10179:2023
01-september-2023
Jekla - Določevanje dušika (v sledeh) v jeklih - Spektrofotometrična metoda
Steels - Determination of nitrogen (trace amounts) - Spectrophotometric method
Stähle - Bestimmung von Stickstoff (Spurengehalte) - Photometrisches Verfahren
Aciers - Détermination de l'azote (à l'état de traces) - Méthode spectrophotométrique
Ta slovenski standard je istoveten z: prEN 10179
ICS:
77.040.30 Kemijska analiza kovin Chemical analysis of metals
77.080.20 Jekla Steels
oSIST prEN 10179:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 10179:2023
oSIST prEN 10179:2023
DRAFT
EUROPEAN STANDARD
prEN 10179
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2023
ICS 77.040.30 Will supersede EN 10179:1989
English Version
Steels - Determination of nitrogen (trace amounts) -
Spectrophotometric method
Aciers - Détermination de l'azote (à l'état de traces) - Stählen - Bestimmung von Stickstoff (Spuren Gehalte) -
Méthode spectrophotométrique Photometrisches Verfahren
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 459/SC 2.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
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 supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 10179:2023 E
worldwide for CEN national Members.
oSIST prEN 10179:2023
prEN 10179:2023 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 5
6 Apparatus . 7
7 Sampling . 7
8 Procedure . 8
8.1 General. 8
8.2 Test portion . 8
8.3 Blank test . 8
8.4 Preparation of the steam distillation apparatus . 8
8.5 Determination . 9
8.6 Establishment of the calibration curve . 10
9 Expression of results . 11
10 Test report . 11
Annex A (informative) Precision data . 12
Bibliography . 16
oSIST prEN 10179:2023
prEN 10179:2023 (E)
European foreword
This document (prEN 10179:2023) has been prepared by Technical Committee CEN/TC 459/SC 2
“Methods of chemical analysis for iron and steel”, the secretariat of which is held by SIS.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 10179:1989.
In comparison with the previous edition, the following technical modifications have been made:
— Normative references: updated;
— Clause 3; Terms and definitions: added;
— References 5.10, 5.11, 5.14, 5.17 and 5.18: added;
— Clause 10: updated;
oSIST prEN 10179:2023
prEN 10179:2023 (E)
1 Scope
This document specifies a spectrophotometric method for the determination of nitrogen in steels.
The method is primarily intended for the determination of total nitrogen in very low contents in non-
alloy steels.
It can be used, however, for any low nitrogen ferrous alloy that is soluble in hydrochloric acid provided
that the acid-resistant form of silicon nitride is not present. This highly resistant nitride has been found
only in samples of silicon steels manufactured without aluminium addition and then only in sheet
material.
The method is applicable to nitrogen contents from 0.000 5 % (by mass) to 0.005 % (by mass).
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.
EN ISO 648, Laboratory glassware — Single-volume pipettes (ISO 648)
EN ISO 1042, Laboratory glassware — One-mark volumetric flasks (ISO 1042)
EN ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical
composition (ISO 14284)
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
4 Principle
Dissolution of the test portion with hydrochloric acid and separation of the acid-insoluble residue by
centrifugation.
Decomposition of the acid-insoluble residue by intense fuming with sulphuric acid and addition of the
extract to the solution of the test portion containing the acid-soluble nitrogen.
Recovery of the total nitrogen as ammonia by steam distillation over sodium hydroxide.
Spectrophotometric measurement of the coloured complex produced by a reaction with indophenol
blue.
oSIST prEN 10179:2023
prEN 10179:2023 (E)
5 Reagents
During the analysis use only reagents of recognized analytical grade and which are known to give a
very low nitrogen bank. The same batch of each reagent shall be used for every test sample and blank
determination in a given series of analysis.
All references to “water” relate to ammonia-free water. Ammonia-free water shall be prepared by
passing distilled water through a cation exchange column (5.1). It is essential that the resin column
+
shall be acid washed before use to ensure its conversion to the hydrogen form, H . This is most
conveniently done by passing 2 l of a solution of hydrochloric acid (5.2), diluted 1 + 9, through the
column and then washing with water until freed from acid.
5.1 High purity iron or steel with a very low nitrogen content
High purity iron powder or very low nitrogen content mild steel [<0,001 % (by mass) nitrogen] may
be used for this purpose. It should be cleaned in the same way as the sample.
5.2 Hydrochloric acid, ρ 1,19 g/ml approximately
5.3 Sulphuric acid, ρ 1,84 g/ml approximately
Sulphuric acid supplied shall be tested individually and selected for a low content of combined
nitrogen in any form (less than 0,5 µg/g). Nitrogen as ammonia will usually be the major source of
contamination and this may be tested by normal methods, but nitrates may also be present and should
be detected by using the method described below.
Add 6 ml of sulphuric acid (5.3) to 2 ml of water and cool to 60 °C. Add one drop of hydrochloric
acid (5.2) and one drop of diphenylamine (5.8). No blue colour should appear.
NOTE Less than 0,1 µg/g can be detected by this test.
5.4 Sulphuric acid, solution 1 + 4
Carefully add 40 ml of sulphuric acid (5.3) to 160 ml of water.
Allow to cool and mix.
5.5 Sodium hydroxide, 400 g/l
Dissolve 400 g of sodium hydroxide in water, dilute to 1 000 ml and mix.
This solution should be prepared in a polyethylene beaker (water-cooled if necessary) and stored in a
polyethylene bottle.
5.6 Barium chloride, 100 g/l
Dissolve 100 g of barium chloride (BaCl · 2H 0) in water, dilute to 1 000 ml and mix.
2 2
5.7 Chromic-sulphuric acid
Dissolve 2 g of chromium trioxide (CrO ) in 50 ml of water and slowly add 100 ml of sulphuric
acid (5.3) with constant stirring.
5.8 Diphenylamine, 1 g/l
To 25 ml of water, whilst stirring, cautiously add 75 ml of sulphuric acid (5.3) then add 0,1 g of
diphenylamine, stir until dissolved and allow to cool.
oSIST prEN 10179:2023
prEN 10179:2023 (E)
5.9 Phenol, 50 g/l
Dissolve 50 g of phenol in water, transfer into a 1 000 ml volumetric flask, dilute to the mark with
water and mix.
Store this solution out of direct sunlight in an amber coloured bottle.
5.10 Potassium iodide (KI)
5.11 Glacial acetic acid, ρ 1,05 g/ml approximately
5.12 Sodium hydroxide - sodium hypochlorite solution
5.12.1 Determination of chlorine in commercial sodium hypochlorite solution
Transfer 10 ml of the sodium hypochlorite solution to be tested into a 250 ml volumetric flask, dilute
to the mark with water and mix.
Transfer, 10 ml of this solution into a 100 ml conical beaker, add 2 g of potassium iodide (5.10) and
10 ml of glacial acetic acid (5.11). Titrate the liberated iodine using sodium thiosulphate (5.15) until
the colour has almost disappeared. Add 2 ml of starch solution (5.16) and continue the titration until
the blue colour has disappeared.
The chlorine content (w ) in per cent (m/v) is given by Formula (1)
Cl
w = 0.886 x V (1)
Cl 1
where:
V is the volume in millilitres of sodium thiosulphate (5.15) used in the titration.
5.12.2 Calculation
The volume, V2, expressed in millilitres, of sodium hypochlorite solution necessary for the preparation
of 1 l of sodium hydroxide - sodium hypochlorite solution (5.12) is given by Formula (2)
2,1××100 70,91 225,7
V = (2)
=
0,886××VV74,44
This volume is equivalent to 2,1 g of chlorine.
5.12.3 Preparation of the solution 5.12
Dissolve 25 g of sodium hydroxide in about 400 ml of water. Exactly add the calculated volume of
sodium hypochlorite solution (5.12.2), dilute to 100 ml and mix.
Store this solution out of direct sunlight in an amber coloured bottle.
5.13 Sodium pentacyanonitrosylferrate (sodium nitroprusside) (Na [Fe(CN) NO] . 2H O)
2 5 2
Dissolve 0,1 g of sodium pentacyanonitrosylferrate in water, dilute to 100 ml and mix.
Prepare this solution freshly each day, store in an amber coloured bottle but do not use until at least
60 min. after the preparation.
5.14 Sodium carbonate (Na CO )
2 3
5.15 Sodium thiosulphate, 0,05 mol/l
oSIST prEN 10179:2023
prEN 10179:2023 (E)
Dissolve 24,821 g of sodium thiosulphate (Na S O . 5H O) in water containing 0,1 g of sodium
2 2 3 2
carbonate (5.14). Transfer into a 1 000 ml volumetric flask, dilute to the mark with water and mix.
5.16 Starch, 5 g/l
Make a suspension of 0,5 g of starch in 10 ml of water. Add to 90 ml of boiling water. Allow to cool,
dilute to 100 ml with water and mix.
5.17 Ammonium chloride standard solution corresponding to 100 µg of nitrogen per millilitre
Dissolve 0,382 g of ammonium chloride (NH Cl), previously dried to constant weight at 105 °C, in
water, transfer into a 1 000 ml one-mark volumetric flask, dilute to the mark with water and mix.
1 ml of this standard solution contains 100 µg of nitrogen.
5.18 Ammonium chloride standard solution corresponding to 1 µg of nitrogen per millilitre
Transfer 10 ml of the nitrogen standard solution (5.17) into a 1 000 ml one-mark volumetric flask,
dilute to the mark with water and mix.
1 ml of this standard solution contains 1 µg of nitrogen.
6 Apparatus
6.1 Ordinary laboratory equipment
All volumetric glassware shall be grade A, in accordance with ISO 648 or ISO 1042, as appropriate.
6.2 Cation exchange column
A column packed with a sulphonated polystyrene cation exchange resin (see Figure 1).
...
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