SIST EN ISO 6145-11:2008

Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 11: Electrochemical generation (ISO 6145-11:2005)

This part of ISO 6145 specifies a method for the preparation of calibration gas mixtures by using electrochemical generation of a calibration component and introduction into a complementary gas flow. By alteration of the gas flow or the charge passed through the cell electrolyte, it is possible to change the composition of the gas mixture. The relative expanded uncertainty of the calibration gas content, U, obtained by multiplying the relative combined standard uncertainties by a coverage factor, k = 2, is not greater than 5 %. The method described in this part of ISO 6145 is intended to be applied to the preparation of calibration gas mixtures in the volume fraction ranges (0,1 to 250) 10-6.

Gasanalyse - Herstellung von Kalibriergasgemischen mit Hilfe von dynamisch-volumetrischen Verfahren - Teil 11: Elektrochemische Herstellung (ISO 6145-11:2005)

Dieser Teil der ISO 6145 legt ein dynamisches Verfahren zur Herstellung von Kalibriergasgemischen fest, bei
dem eine Kalibrierkomponente elektrochemisch erzeugt und in einen Grundgasstrom eingespeist wird. Durch
Änderung des Gasstroms oder der durch den Zellelektrolyten geleiteten Ladung lässt sich die Zusammensetzung
des Gasgemischs ändern. Die relative erweiterte Unsicherheit U des Kalibriergasgehalts,
bestimmt durch Multiplikation der relativen kombinierten Standardunsicherheit mit einem Überdeckungsfaktor
k = 2, ist nicht größer als 5 %.
Das in diesem Teil der ISO 6145 beschriebene Verfahren ist für Anwendungen zur Herstellung von Kalibriergasgemischen
mit Volumenanteilen im Bereich von (0,1 bis 250) × 10–6 vorgesehen.
ANMERKUNG 1 Gase, die elektrochemisch erzeugt werden können, sind Sauerstoff (O2), Wasserstoff (H2), Cyanwasserstoff
(HCN), Schwefelwasserstoff (H2S), Chlor (Cl2), Brom (Br2), Chlordioxid (ClO2), Ammoniak (NH3), Stickstoffmonoxid
(NO), Stickstoff (N2), Kohlenstoffdioxid (CO2), Phosphorwasserstoff (PH3), Arsenwasserstoff (AsH3) und Ozon (O3).
ANMERKUNG 2 Die Vorteile dieses Verfahrens bestehen darin, dass sich stabile Gasgemische schnell, innerhalb von
Minuten, herstellen lassen.
ANMERKUNG 3 Gasmischsysteme auf der Grundlage von elektrochemischer Herstellung und thermischen Massenstromreglern,
mit der Möglichkeit von Computerunterstützung und automatischer Steuerung, sind kommerziell verfügbar.
Ein Beispiel wird in Anhang A angegeben.

Analyse des gaz - Préparation des mélanges de gaz pour étalonnage à l'aide de méthodes volumétriques dynamiques - Partie 11: Génération électrochimique (ISO 6145-11:2005)

L'ISO 6145‑11:2005 spécifie une méthode de préparation des mélanges de gaz pour étalonnage par génération électrochimique d'un constituant pour étalonnage et son introduction dans un gaz de complément. En modifiant le débit du gaz ou la charge traversant l'électrolyte de la cellule, il est possible de modifier la composition du mélange de gaz. L'incertitude relative élargie de la teneur en gaz pour étalonnage, U, obtenue en multipliant les incertitudes-types relatives combinées par un facteur d'élargissement, k = 2, n'est pas supérieure à 5 %.
La méthode décrite dans la présente partie de l'ISO 6145‑11:2005 est destinée à être appliquée à la préparation de mélanges de gaz pour étalonnage dans les gammes de fractions volumiques de (0,1 à 250) x 10–6.

Analiza plinov - Priprava kalibracijske plinske zmesi z uporabo dinamičnih volumetričnih metod - 11. del: Elektrokemična proizvodnja (ISO 6145-11:2005)

General Information

• Status: Published
• Publication Date: 04-Sep-2008
• ICS: 71.040.40 - Chemical analysis
• Technical Committee: NAD - Petroleum products, lubricants and related products
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 29-Aug-2008
• Due Date: 03-Nov-2008
• Completion Date: 05-Sep-2008
• Ref Project: EN ISO 6145-11:2008 - Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 11: Electrochemical generation (ISO 6145-11:2005)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 6145-11:2008
01-oktober-2008
$QDOL]DSOLQRY3ULSUDYDNDOLEUDFLMVNHSOLQVNH]PHVL]XSRUDERGLQDPLþQLK
YROXPHWULþQLKPHWRGGHO(OHNWURNHPLþQDSURL]YRGQMD,62
Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods
- Part 11: Electrochemical generation (ISO 6145-11:2005)
Gasanalyse - Herstellung von Kalibriergasgemischen mit Hilfe von dynamisch-
volumetrischen Verfahren - Teil 11: Elektrochemische Herstellung (ISO 6145-11:2005)
Analyse des gaz - Préparation des mélanges de gaz pour étalonnage à l'aide de
méthodes volumétriques dynamiques - Partie 11: Génération électrochimique (ISO 6145-
11:2005)
Ta slovenski standard je istoveten z: EN ISO 6145-11:2008
ICS:
71.040.40 Kemijska analiza Chemical analysis
SIST EN ISO 6145-11:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 6145-11:2008

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SIST EN ISO 6145-11:2008
EUROPEAN STANDARD
EN ISO 6145-11
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2008
ICS 71.040.40

English Version
Gas analysis - Preparation of calibration gas mixtures using
dynamic volumetric methods - Part 11: Electrochemical
generation (ISO 6145-11:2005)
Analyse des gaz - Préparation des mélanges de gaz pour Gasanalyse - Herstellung von Kalibriergasgemischen mit
étalonnage à l'aide de méthodes volumétriques Hilfe von dynamisch-volumetrischen Verfahren - Teil 11:
dynamiques - Partie 11: Génération électrochimique (ISO Elektrochemische Herstellung (ISO 6145-11:2005)
6145-11:2005)
This European Standard was approved by CEN on 30 July 2008.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 6145-11:2008: E
worldwide for CEN national Members.

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SIST EN ISO 6145-11:2008
EN ISO 6145-11:2008 (E)
Contents Page
Foreword.3

2

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SIST EN ISO 6145-11:2008
EN ISO 6145-11:2008 (E)
Foreword
The text of ISO 6145-11:2005 has been prepared by Technical Committee ISO/TC 158 “Analysis of gases” of
the International Organization for Standardization (ISO) and has been taken over as EN ISO 6145-11:2008 by
Technical Committee CEN/TC N21 “Gaseous fuels and combustible gas” the secretariat of which is held by
CMC.
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 February 2009, and conflicting national standards shall be withdrawn
at the latest by February 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 6145-11:2005 has been approved by CEN as a EN ISO 6145-11:2008 without any
modification.

3

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SIST EN ISO 6145-11:2008

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SIST EN ISO 6145-11:2008


INTERNATIONAL ISO
STANDARD 6145-11
First edition
2005-10-15

Gas analysis — Preparation of calibration
gas mixtures using dynamic volumetric
methods —
Part 11:
Electrochemical generation
Analyse des gaz — Préparation des mélanges de gaz pour étalonnage
à l'aide de méthodes volumétriques dynamiques —
Partie 11: Génération électrochimique




Reference number
ISO 6145-11:2005(E)
©
ISO 2005

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SIST EN ISO 6145-11:2008
ISO 6145-11:2005(E)
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©  ISO 2005
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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Published in Switzerland

ii © ISO 2005 – All rights reserved

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SIST EN ISO 6145-11:2008
ISO 6145-11:2005(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Procedure . 2
3.1 Principle. 2
3.2 Complementary gas. 2
3.3 Electrolytic systems for gas generation. 2
3.4 Apparatus . 3
3.4.1 Cell construction. 3
3.4.2 Current supply and gas flow control . 3
3.5 Gas mixture preparation . 3
3.5.1 Complementary gas. 3
3.5.2 Voltage supply . 3
3.5.3 Calculation of gas mixture content. 4
4 Uncertainty evaluation . 6
4.1 Introduction . 6
4.2 Sources of uncertainty. 6
4.2.1 Complementary gas flow . 6
4.2.2 Gas generation. 6
4.2.3 Absorption of generated gas in the cell electrolyte. 6
4.2.4 Effect of moisture content . 6
4.2.5 Effect of temperature. 6
4.2.6 Purity of electrolytic chemicals. 6
4.2.7 Impurities in complementary gas. 7
4.3 Uncertainty of volume fraction. 7
5 Electrochemical cell design. 7
Annex A (informative) Example of a commercial electrochemical cell . 9
Annex B (informative) Schematics of electrolytic cells used for gas generation. 11
Annex C (informative) Schematic of electrical supply to gas generation cell . 12
Annex D (informative) Decomposition voltages of solutions between smooth platinum electrodes . 13
Bibliography . 14

© ISO 2005 – All rights reserved iii

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SIST EN ISO 6145-11:2008
ISO 6145-11:2005(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 6145-11 was prepared by Technical Committee ISO/TC 158, Analysis of gases.
ISO 6145 consists of the following parts, under the general title Gas analysis — Preparation of calibration gas
mixtures using dynamic volumetric methods:
⎯ Part 1: Methods of calibration
⎯ Part 2: Volumetric pumps
⎯ Part 4: Continuous syringe injection method
⎯ Part 5: Capillary calibration devices
⎯ Part 6: Critical orifices
⎯ Part 7: Thermal mass-flow controllers
⎯ Part 8: Diffusion method
⎯ Part 9: Saturation method
⎯ Part 10: Permeation method
⎯ Part 11: Electrochemical generation
Part 3 to ISO 6145, entitled Periodic injections into a flowing gas stream, has been withdrawn by Technical
Committee ISO/TC 158, Analysis of gases.
iv © ISO 2005 – All rights reserved

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SIST EN ISO 6145-11:2008
ISO 6145-11:2005(E)
Introduction
This part of ISO 6145 is one of a series of standards dealing with the various dynamic volumetric methods
used for the preparation of calibration gas mixtures.
Electrochemical gas generation can be used to produce calibration gas mixtures containing calibration
components which, because of their corrosive nature or low content, are unlikely to be stable in high-pressure
cylinders.
© ISO 2005 – All rights reserved v

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SIST EN ISO 6145-11:2008

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SIST EN ISO 6145-11:2008
INTERNATIONAL STANDARD ISO 6145-11:2005(E)

Gas analysis — Preparation of calibration gas mixtures using
dynamic volumetric methods —
Part 11:
Electrochemical generation
1 Scope
This part of ISO 6145 specifies a method for the preparation of calibration gas mixtures by using
electrochemical generation of a calibration component and introduction into a complementary gas flow. By
alteration of the gas flow or the charge passed through the cell electrolyte, it is possible to change the
composition of the gas mixture. The relative expanded uncertainty of the calibration gas content, U, obtained
by multiplying the relative combined standard uncertainties by a coverage factor, k = 2, is not greater than 5 %.
The method described in this part of ISO 6145 is intended to be applied to the preparation of calibration gas
–6
mixtures in the volume fraction ranges (0,1 to 250) × 10 .
NOTE 1 Gases that can be produced by electrochemical generation are oxygen (O ), hydrogen (H ), hydrogen
2 2
cyanide (HCN), hydrogen sulfide (H S), chlorine (Cl ), bromine (Br ), chlorine dioxide (ClO ), ammonia (NH ), nitric
2 2 2 2 3
oxide (NO), nitrogen (N ), carbon dioxide (CO ), phosphine (PH ), arsine (AsH ) and ozone (O ).
2 2 3 3 3
NOTE 2 The merits of the method are that a stable calibration gas mixture can be quickly prepared within minutes.
NOTE 3 Gas blending systems based on electrochemical generation and thermal mass flow controllers, with the facility
of computerization and automatic control, are commercially available. An example is given in Annex A.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 6143, Gas analysis — Comparison methods for determining and checking the composition of calibration
gas mixtures
ISO 6145-1, Gas analysis — Preparation of calibration gas mixtures using dynamic volumetric methods —
Part 1: Methods of calibration
ISO 6145-7:2001, Gas analysis — Preparation of calibration gas mixtures using dynamic volumetric
methods — Part 7: Thermal mass-flow controllers
© ISO 2005 – All rights reserved 1

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SIST EN ISO 6145-11:2008
ISO 6145-11:2005(E)
3 Procedure
3.1 Principle
Electrochemical gas generation is a fundamental method in which the quantity of the calibration gas
component generated is proportional to the charge passed. The proportionality factor is the reciprocal of the
Faraday constant [the electrical charge carried by one mole of electrons (or singly charged ions)], which is
equal to the product of the Avogadro constant (N ) and the charge of an electron (–e).
A
F = N ⋅ e (1)
A
where
–8
F is 96 485,341 5 C/mol with a relative uncertainty of 4,0 × 10 (see References [1], [2] and [3]).
The passage of accurately determined electrical current through a cell determines the gas output provided the
conditions given in Clause 5 are applied.
3.2 Complementary gas
The flow rate of complementary gas shall be determined by one of the methods given in ISO 6145-1.
3.3 Electrolytic systems for gas generation
Table 1 lists some examples of gases which can be prepared in quantitative yield by direct electrolysis, using
platinum and other electrodes. Also included is an example of the suppression of an unwanted constituent by
adsorption on activated carbon surrounding the appropriate electrode.
Table 1 — Electrolysis systems for gas generation
Gas required Electrolysis system Gas liberated at other Yield
electrode mole of required gas per
charge numerically equal
to Faraday number
O or H Pt, H SO , Pt H or O 1/4 (O )

2 2 2 4 2 2 2
Pt, K SO , Pt 1/2 (H )
2 4 2
Pt, KOH, Pt
O Pt, H SO , Hg SO , +C, Hg nil 1/4
2 2 4 2 4
Pt, neutral solution, active C
Pt, KOH, HgO, +C, Hg
Pt, KOH, CdO, Cd
N Pt, N H , H SO , Pt H 1/4
2 2 4 2 4 2
Cl Pt, NaCl, Pt H 1/2

2 2
CO Pt, H C O , Pt H 1

2 2 2 4 2

a
NO Pt, (NOH)SO , + H SO , Pt O 1
4 2 4 2

a [4]
This system has also been used for the generation of nitrogen dioxide .
2 © ISO 2005 – All rights reserved

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SIST EN ISO 6145-11:2008
ISO 6145-11:2005(E)
3.4 Apparatus
3.4.1 Cell construction
Cell construction shall be designed to ensure that the generated calibrated component is transferred into the
complementary gas stream at maximum efficiency suitable for calibration purposes. Some of the conditions
that shall be fulfilled for the operation of an electrolytic cell used for this purpose are given in Clause 5.
Examples of electrolytic cells are given in Figures B.1 and B.2.
3.4.2 Current supply and gas flow control
3.4.2.1 The content of the calibration gas produced from the system is dependent on three factors:
a) the current supplied through the cell which generates a volume flow rate of the calibration gas component;
b) the (volume) flow rate of the complementary gas; and
c) the cell efficiency.
NOTE Cell efficiency is the fraction recovery of calibration component over the calculated quantity generated by the
current supplied to the cell (see 4.2.3). It depends on the design of the cell. Practical hints on design are given in Clause 5
and an example is given in Annex C.
3.4.2.2 A battery, capable of supplying voltage in the range 0,5 V to 1,0 V, and a milliamperemeter with a
measurement range of 0,5 mA to 5,0 mA with an uncertainty of 1,0 %, are suitable. DC generators are an
alternative but may pass an AC ripple, which can affect the electrolysis process.
3.4.2.3 A flow measuring unit (e.g. a thermal mass-flow meter) that has been calibrated for the
complementary gas between a volume f
...