prEN ISO 23320

Workplace air - Gases and vapours - Requirements for evaluation of measuring procedures using diffusive samplers (ISO/DIS 23320:2021)

This document specifies performance requirements and test methods under prescribed laboratory conditions for the evaluation of diffusive samplers and of procedures using these samplers for the determination of gases and vapours in workplace atmospheres.
This document is applicable to diffusive samplers and measuring procedures using these samplers in which sampling and analysis are carried out in separate stages.
This document is not applicable to
—   diffusive samplers which are used for the direct determination of concentrations,
—   diffusive samplers which rely on sorption into a liquid.
This document addresses requirements for method developers and/or manufacturers.
NOTE   For the purposes of this document a manufacturer can be any commercial or non-commercial entity.

Luft am Arbeitsplatz - Gase und Dämpfe - Anforderungen an die Evaluierung von Messverfahren mit Diffusionssammlern (ISO/DIS 23320:2021)

Dieses Dokument legt Anforderungen an die Leistungsfähigkeit und Prüfverfahren für die Evaluierung von Diffusionssammlern ("Passivsammlern") unter vorgegebenen Laborbedingungen fest, sowie Verfahren, die diese Sammler zur Bestimmung von Gasen und Dämpfen in der Arbeitsplatzatmosphäre verwenden.
Dieses Dokument gilt für Diffusionssammler und Messverfahren, wie ISO 16200-2 und ISO 16017-2, die diese Sammler, bei denen Probenahme und Analyse in getrennten Schritten vorgenommen werden, verwenden.
Dieses Dokument ist nicht anwendbar für
- Diffusionssammler, die zur direkten Konzentrationsbestimmung verwendet werden, und
- Diffusionssammler, deren Funktionsweise auf Sorption in einer Flüssigkeit beruht.
Dieses Dokument behandelt Anforderungen an Verfahrensentwickler und/oder -hersteller.
ANMERKUNG Für die Anwendung dieses Dokuments kann ein Hersteller jede kommerzielle oder nicht kommerzielle Einrichtung sein.

Air des lieux de travail - Gazes et vapeurs - Exigences pour l'évaluation des procédures pour le mesurage à l'aide de dispositifs de prélèvement par diffusion (ISO/DIS 23320:2021)

Zrak na delovnem mestu - Plini in pare - Zahteve za vrednotenje merilnih postopkov z difuzijskimi vzorčevalniki (ISO/DIS 23320:2021)

General Information

• Status: Not Published
• ICS: 13.040.30 - Workplace atmospheres
• Technical Committee: CEN/TC 137 - Assessment of workplace exposure
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Due Date: 14-Oct-2021
• Completion Date: 14-Oct-2021
• Ref Project: oSIST prEN ISO 23320:2021 - Workplace air - Gases and vapours - Requirements for evaluation of measuring procedures using diffusive samplers (ISO/DIS 23320:2021)

RELATIONS

• Revised: EN 838:2010 - Workplace exposure - Procedures for measuring gases and vapours using diffusive samplers - Requirements and test methods
• Effective Date: 10-Jun-2020

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN ISO 23320:2021
01-maj-2021
Zrak na delovnem mestu - Plini in pare - Zahteve za vrednotenje merilnih
postopkov z difuzijskimi vzorčevalniki (ISO/DIS 23320:2021)
Workplace air - Gases and vapours - Requirements for evaluation of measuring
procedures using diffusive samplers (ISO/DIS 23320:2021)
Luft am Arbeitsplatz - Gase und Dämpfe - Anforderungen an die Evaluierung von
Messverfahren mit Diffusionssammlern (ISO/DIS 23320:2021)

Air des lieux de travail - Gazes et vapeurs - Exigences pour l'évaluation des procédures

pour le mesurage à l'aide de dispositifs de prélèvement par diffusion (ISO/DIS
23320:2021)
Ta slovenski standard je istoveten z: prEN ISO 23320
ICS:
13.040.30 Kakovost zraka na delovnem Workplace atmospheres
mestu
oSIST prEN ISO 23320:2021 en,fr,de

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

---------------------- Page: 1 ----------------------
oSIST prEN ISO 23320:2021
---------------------- Page: 2 ----------------------
oSIST prEN ISO 23320:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 23320
ISO/TC 146/SC 2 Secretariat: ANSI
Voting begins on: Voting terminates on:
2021-03-24 2021-06-16
Workplace air — Gases and vapours — Requirements
for evaluation of measuring procedures using diffusive
samplers
ICS: 13.040.30
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 23320:2021(E)
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. ISO 2021
---------------------- Page: 3 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 2

5 Types of samplers ................................................................................................................................................................................................ 3

6 Requirements .......................................................................................................................................................................................................... 3

6.1 General ........................................................................................................................................................................................................... 3

6.2 Sampler requirements ...................................................................................................................................................................... 3

6.2.1 Nominal uptake rate ..................................................................................................................................................... 3

6.2.2 Air velocity/sampler orientation ....................................................................................................................... 4

6.2.3 Sampler leak test ............................................................................................................................................................. 4

6.2.4 Shelf life ................................................................................................................................................................................... 4

6.2.5 Sampler identification (for commercially available diffusive samplers) ........................ 4

6.2.6 Marking .................................................................................................................................................................................... 4

6.2.7 Instructions for use........................................................................................................................................................ 4

6.3 Measuring procedure requirements .................................................................................................................................... 5

6.3.1 Sampling procedure requirements .................................................................................................................. 5

6.3.2 Analytical procedure requirements ................................................................................................................ 5

6.3.3 Expanded uncertainty ................................................................................................................................................. 6

6.3.4 Method description ....................................................................................................................................................... 6

7 General test conditions .................................................................................................................................................................................. 7

7.1 Reagents........................................................................................................................................................................................................ 7

7.2 Apparatus .................................................................................................................................................................................................... 7

7.3 Independent method ......................................................................................................................................................................... 7

7.4 Generation of a calibration gas mixture ............................................................................................................................ 8

7.4.1 General...................................................................................................................................................................................... 8

7.4.2 Determination of mass concentration ........................................................................................................... 8

8 Test methods ............................................................................................................................................................................................................. 9

8.1 General ........................................................................................................................................................................................................... 9

8.2 Sampler test methods ....................................................................................................................................................................... 9

8.2.1 Determination of (nominal) uptake rate ..................................................................................................... 9

8.2.2 Air velocity .........................................................................................................................................................................10

8.2.3 Sampler leak test ..........................................................................................................................................................11

8.2.4 Shelf life (for Type A impregnated supports) ......................................................................................11

8.2.5 Sampler identification ..............................................................................................................................................12

8.2.6 Marking .................................................................................................................................................................................12

8.2.7 Instructions for use.....................................................................................................................................................12

8.3 Measuring procedure test methods ...................................................................................................................................12

8.3.1 Determination of the sampling conditions ............................................................................................12

8.3.2 Analytical procedure test methods ...............................................................................................................13

8.3.3 Method recovery and method precision ..................................................................................................15

8.4 Uncertainty of measurement ...................................................................................................................................................17

8.4.1 Identification of random and non-random uncertainty components .............................17

8.4.2 Estimation of individual uncertainty components ..........................................................................17

8.4.3 Calculation of expanded uncertainty ..........................................................................................................18

9 Test report ................................................................................................................................................................................................................19

Annex A (informative) Fundamentals of diffusive sampling ....................................................................................................20

Annex B (informative) Estimation of uncertainty of measurement ..................................................................................23

© ISO 2021 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)

Annex C (informative) Calculation of uptakes rates from diffusion coefficients .................................................33

Annex D (informative) Example of estimation of expanded uncertainty ....................................................................35

Bibliography .............................................................................................................................................................................................................................38

iv © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

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

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

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

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

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

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

on the ISO list of patent declarations received (see www .iso .org/ patents).

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

constitute an endorsement.

For an explanation 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 146, Air quality, Subcommittee SC 2,

Workplace atmospheres.

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.
© ISO 2021 – All rights reserved v
---------------------- Page: 7 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)
Introduction

This document provides a framework for assessing the performance of procedures for measuring

gases and vapours against the general requirements for the performance of procedures for measuring

chemical agents in workplace atmospheres as specified in ISO 20581. These performance criteria

include maximum values of expanded uncertainty achievable under prescribed laboratory conditions

for the methods to be used.

This document enables manufacturers and users of diffusive samplers and developers and users of

procedures for measuring gases and vapours to adopt a consistent approach to method validation.

This document is based on EN 838:2010, published by the European Committee for Standardization

(CEN) and is complementary also to ISO 16107.
vi © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
oSIST prEN ISO 23320:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 23320:2021(E)
Workplace air — Gases and vapours — Requirements
for evaluation of measuring procedures using diffusive
samplers
1 Scope

This document specifies performance requirements and test methods under prescribed laboratory

conditions for the evaluation of diffusive samplers and of procedures using these samplers for the

determination of gases and vapours in workplace atmospheres.

This document is applicable to diffusive samplers and measuring procedures using these samplers,

such as ISO 16200-2 and ISO 16017-2, in which sampling and analysis are carried out in separate stages.

This document is not applicable to

— diffusive samplers which are used for the direct determination of concentrations, and

— diffusive samplers which rely on sorption into a liquid.
This document addresses requirements for method developers and/or manufacturers.

NOTE For the purposes of this document a manufacturer can be any commercial or non-commercial entity.

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 20581, Workplace air — General requirements for the performance of procedures for the measurement

of chemical agents

ISO 22065, Workplace air — Gases and vapours — Requirements for evaluation of measuring procedures

using pumped samplers
ISO 18158, Workplace air — Terminology
ISO 8655-2:2002, Piston-operated volumetric apparatus — Part 2: Piston pipettes

ISO 8655-6:2002, Piston-operated volumetric apparatus — Part 6: Gravimetric methods for the

determination of measurement error
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 18158 and ISO 20581 apply.

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 http:// www .electropedia .org/
© ISO 2021 – All rights reserved 1
---------------------- Page: 9 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)
4 Symbols and abbreviated terms

NOTE See 8.4 and Annex C for symbols used in conjunction with uncertainty of measurement only.

A cross-sectional area of sorption surface, in square centimetres (cm )
CRM certified reference material
2 −1

D diffusion coefficient of an analyte, in square centimetres per minute (cm ∙ min )

2 −1

D diffusion coefficient of analyte 1, in square centimetres per minute (cm ∙ min )

2 −1

D diffusion coefficient of analyte 2, in square centimetres per minute (cm ∙ min )

l length of static air layer in sampler (or equivalent for permeation types), in centimetres (cm)

m mass of analyte desorbed from blank sampler, in nanograms (ng)
m mass of analyte desorbed, in nanograms (ng)

m mass of the analyte which can diffuse to a suitable sorbent within a certain time, i.e. the mass

uptake of a diffusive sampler, in nanograms (ng)
m mass loss from permeation tube, in micrograms per minute (µg ∙ min )
M molar mass of analyte, in grams per mole (g ∙ mol )
n number of replicate samples
OELV occupational exposure limit value
p actual pressure of the test atmosphere sampled, in kilopascals (kPa)
R recovery
R analytical recovery
RH relative humidity of the test atmosphere sampled, in percent (%)
t exposure time, in minutes (min)
T temperature of the test atmosphere sampled, in Kelvin (K)
3 −1
uptake rate, in cubic centimetres per minute (cm ∙ min )
−1 −1

uptake rate, in nanograms per parts per million (volume fraction) per minute (ng ∙ ppm ∙ min )

3 −1
uptake rate of analyte 1, in cubic centimetres per minute (cm ∙ min )
3 −1
uptake rate of analyte 2, in cubic centimetres per minute (cm ∙ min )

flow rate into the exposure chamber, for example, in litres per minute (l ∙ min )

mass concentration of the analyte in the calibration gas mixture, in milligrams per cubic metre

(mg ∙ m )
mass concentration in parts per million (ppm);

β mass concentration of the given analyte at the beginning of the diffusion layer (i.e. at the distance

l from the surface of the sorbent), in milligrams per cubic metre (mg ∙ m )
2 © ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)

β mass concentration of the given analyte at the end of the diffusion layer (i.e. at the surface of

the sorbent), in milligrams per cubic metre (mg ∙ m )

mean mass concentration of the analyte recovered from the test gas atmosphere, in milligrams

a,R
per cubic metre (mg ∙ m );

β mass concentration of the calibration gas mixture, in milligrams per cubic metre (mg ∙ m )

ϑ temperature of the test atmosphere sampled, in degree Celsius (°C)
K coefficient of variation (CV)
⌀ volume fraction of the analyte, in microlitres per litre (µl ∙ l )

1) The predecessor term "relative standard deviation" is deprecated and has been replaced by the

term "coefficient of variation". See also ISO 3534-1:2006, 2.38, Note 2.
5 Types of samplers

Samplers for gases and vapours can be divided into type A samplers and type B samplers:

Type A samplers rely on sorption onto a solid or onto a support impregnated with a reagent, desorption

with solvent, and subsequent analysis of the desorbate. They are usually made of polypropylene or

glass and consist of one or more sorbent layers, and contain an active sorbent (e.g. activated carbon) or

a support impregnated with reagent.

Type B samplers rely on sorption onto a solid or onto a support impregnated with a reagent, thermal

desorption, and analysis of the desorbate. They are usually made of glass or metal, are sealed with

removable fittings and consist of one or more beds of sorbent (e.g. porous polymer resin).

6 Requirements
6.1 General

Some requirements (see 6.2) shall be initially verified by the manufacturer once for each type of

sampler. Other requirements (see 6.3) shall be verified for each combination sampler/chemical agent.

Measuring procedures shall meet the requirements for measuring procedures specified in 6.3. When

use of a sampler for measurement of a particular gas or vapour is claimed, the sampler shall meet the

requirements specified in 6.2.

NOTE 1 No useful performance requirements can be given for the effect of interferents (with the exception

of relative humidity). The effect of interferents is difficult to predict for a non-ideal sorbent without adsorption

isotherm data on mixed systems which is normally unavailable. However the user of diffusive samplers is

cautioned that the adsorption of water vapour on certain sorbents, e.g. activated carbon and silica gel, can have a

large effect on sampler capacity and analytical recovery.

NOTE 2 Because of the known effect of pressure on diffusion coefficients, a pressure test is not necessary.

6.2 Sampler requirements
6.2.1 Nominal uptake rate

The nominal uptake rate and the coefficient of variation shall be provided by the manufacturer.

© ISO 2021 – All rights reserved 3
---------------------- Page: 11 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)
6.2.2 Air velocity/sampler orientation

The manufacturer shall test the working range of air velocity and the influence of sampler orientation

in accordance with 8.2.2.
6.2.3 Sampler leak test

When tested in accordance with 8.2.3, any additional analyte determined above the blank value (see

6.3.2.3) shall be less the one-third of the calculated mass uptake by the sampler for 30 min exposure to

a concentration of 0,1 OELV.
6.2.4 Shelf life

The manufacturer shall specify the shelf life of the diffusive sampler when stored in its original package.

During this period the sampler shall fulfil all requirements.
6.2.5 Sampler identification (for commercially available diffusive samplers)
Samplers shall be uniquely identified.
6.2.6 Marking
Diffusive samplers shall be marked with at least the following:
a) manufacturer's name;
b) product identification;
c) batch identification;
d) shelf life (if applicable);
e) number of this document.

If required due to limited space, the marking may be placed on the packaging of the diffusive sampler.

However, the manufacturer's name and product identification shall be indicated on the diffusive

sampler.
6.2.7 Instructions for use

The instructions for use supplied with the diffusive sampler shall be written in the principal language(s)

used in the countries where the diffusive sampler is to be marketed. Where appropriate, the instructions

for use shall contain directly and by reference to an online document, at least the following information:

a) designated use (general purpose for a number of gases and vapours or, specific, for a particular gas

or vapour, see 6.1);
b) blank value (only when used for a particular gas or vapour, see 6.1);

c) nominal uptake rate for the substances for which the diffusive sampler is intended to use;

d) directions for proper handling of the diffusive sampler, including opening and closing;

e) general information on the principle of use, for example, sorbent type, reaction of the reagent

impregnated solid, desorption method;
f) information on storage and transport;
g) air velocity range in which the sampler can be used;
h) orientation;
4 © ISO 2021 – All rights reserved
---------------------- Page: 12 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)
i) information on health or environmental hazards and method of disposal.

The general information on the principle of use can be given in additional literature.

6.3 Measuring procedure requirements
6.3.1 Sampling procedure requirements
6.3.1.1 Sampling time

Sampling time shall be established according to concentration range of the compounds of interest over

which measurements are to be made, i.e. up to two times the OELV, see ISO 20581, and taking into

account the nominal or theoretical uptake rate.
6.3.1.2 Bias due to the selection of a non-ideal sorbent (back diffusion)
When tested in accordance with 8.3.1.1, the bias shall be ≤ 10 %.
6.3.1.3 Uptake rate

If it is possible to calculate the ideal steady-state value in accordance with 8.2.1, the nominal uptake

rate, determined in accordance with 8.2.1, shall be within ± 25 % of the steady-state value.

6.3.1.4 Storage conditions after sampling

The storage conditions after sampling shall be specified. When tested in accordance with 8.3.1.3, the

mean value of the recovery after storage shall not differ by more than 10 % from the value before

storage.
6.3.2 Analytical procedure requirements
6.3.2.1 Limit of quantification

The limit of quantification as determined in 8.3.2.1 for long-term OELVs shall be lower than the mass

collected by the sampler at a concentration of 0,1 OELV for 8 h.

The limit of quantification for short-term OELVs shall be lower than the mass collected by the sampler

at a concentration of 0,5 OELV for 15 min.

If the sampler is to be used for shorter reference periods the limit of quantification also shall be able to

be measured at those periods.
6.3.2.2 Analytical recovery
When tested in accordance with 8.3.2.2 the analytical recovery R shall be
for type A samplers: R ≥ 75 % with K ≤ 10 % at each loading, and
an v
for type B samplers: R ≥ 95 % with K ≤ 10 % at each loading.
an v

Where the analytical recovery cannot be achieved the user shall take care that the measuring procedure

meets all other requirements of this document and ISO 20581.
6.3.2.3 Blank value

In order to obtain acceptable values for the quantification limit of the method, the blank value of the

sampling media should be as low as technically possible.
© ISO 2021 – All rights reserved 5
---------------------- Page: 13 ----------------------
oSIST prEN ISO 23320:2021
ISO/DIS 23320:2021(E)

The blank value as tested in 8.3.2.3 shall be less than the limit of quantification as determined in

accordance with 8.3.2.1 or otherwise it can be subtracted from the result but the standard deviation of

the blank value will contribute to the expanded uncertainty of the measuring procedure.

Where it is known that the blank value is significant and varies between batches of samplers, it shall be

checked on each batch of samplers.

To eliminate any contamination which could occur during storage before use, Type B samplers should

be cleaned before sampling by taking them through the thermal desorption procedure.

This cleaning process should be carried out as close as possible to the time when the samplers will

be used.
6.3.3 Expanded uncertainty

When tested in accordance with 8.3 the expanded uncertainty calculated in accordance with 8.4 shall

meet the requirements given in ISO 20581.

The expanded uncertainty requirement shall be met from 10 °C to 40 °C and at relative humidities from

20 % to 80 %. Above 30 °C the use of correction factors is permitted to meet this requirement.

In addition, the performance criteria should also be met under a wider variety of environmental

influences, representative of workplace conditions.
6.3.4 Method description
6.3.4.1 Scope of the measuring procedure
The scope of the measuring procedure shall include information on the following:
a) principle of the method;
b) chemical agents covered by the measuring procedure;
c) analytical technique used;
d) working ranges;

e) chemical agents for which the measuring procedure is known to be adequate but not completely

validated according to this document, es
...