EN ISO 21832:2020

Workplace air - Metals and metalloids in airborne particles - Requirements for evaluation of measuring procedures (ISO 21832:2018)

This document specifies performance requirements and test methods for the evaluation of procedures for measuring metals and metalloids in airborne particles sampled onto a suitable collection substrate.
This document specifies a method for estimating the uncertainties associated with random and systematic errors and combining them to calculate the expanded uncertainty of the measuring procedure as a whole, as prescribed in ISO 20581.
This document is applicable to measuring procedures in which sampling and analysis is carried out in separate stages, but it does not specify performance requirements for collection, transport and storage of samples, since these are addressed in EN 13205-1 and ISO 15767.
This document does not apply to procedures for measuring metals or metalloids present as inorganic gases or vapours (e.g. mercury, arsenic) or to procedures for measuring metals and metalloids in compounds that could be present as a particle/vapour mixture (e.g. arsenic trioxide).

Luft am Arbeitsplatz - Metalle und Metalloide in luftgetragenen Partikeln - Anforderungen an die Evaluierung von Messverfahren (ISO 21832:2018)

Dieses Dokument legt Anforderungen an die Leistungsfähigkeit sowie Prüfverfahren zur Evaluierung von Messverfahren zur quantitativen Bestimmung von Metallen und Metalloiden in luftgetragenen Partikeln fest, die auf einem geeigneten Substrat, z. B. einem Filter, gesammelt wurden.
Dieses Dokument legt, wie nach ISO 20581 vorgeschrieben, ein Verfahren fest, mit dem Unsicherheiten, die mit zufälligen und systematischen Fehlern zusammenhängen, abgeschätzt werden können. Außerdem wird deren Kombination zum Berechnen der erweiterten Unsicherheit des Messverfahrens als Ganzes vorgeschrieben.
Dieses Dokument ist anzuwenden für Messverfahren, bei denen Probenahme und Analyse in getrennten Schritten durchgeführt werden. Es werden jedoch keine Leistungsanforderungen für die Sammlung, den Transport und die Lagerung von Proben festgelegt, da diese Aspekte in EN 13205 1 und ISO 15767 behandelt werden.
Dieses Dokument ist nicht anzuwenden für Verfahren zur quantitativen Bestimmung von Metallen und Metalloiden, die in anorganischen Gasen oder Dämpfen vorhanden sind, wie z. B. von Quecksilber, Arsen, oder für Verfahren zur quantitativen Bestimmung von Metallen und Metalloiden in Verbindungen, die als Partikel-Dampf-Gemisch vorliegen könnten (z. B. Arsentrioxid).

Air des lieux de travail - Métaux et métalloïdes dans les particules en suspension dans l'air - Exigences relatives à l'évaluation des procédures de mesure (ISO 21832:2018)

Le présent document précise les exigences de performance et les méthodes d'essai pour l'évaluation des procédures de mesure des métaux et métalloïdes présents dans les particules en suspension dans l'air échantillonnées sur un substrat de collecte approprié.
Le présent document spécifie une méthode permettant d'estimer les incertitudes associées aux erreurs aléatoires et systématiques et de les combiner pour calculer l'incertitude élargie de la procédure de mesure dans son ensemble, comme spécifié dans l'ISO 20581.
Le présent document s'applique aux procédures de mesure qui dissocient l'étape de prélèvement de l'étape d'analyse, mais il ne précise aucune exigence de performance concernant la collecte, le transport et le stockage des échantillons, dans la mesure où ces exigences sont traitées dans l'EN 13205‑1 et l'ISO 15767.
Le présent document ne s'applique pas aux procédures de mesure des métaux ou métalloïdes présents dans des gaz ou des vapeurs inorganiques (par exemple le mercure, l'arsenic), ni aux procédures de mesure des métaux et métalloïdes présents dans des composés pouvant exister sous forme de mélange de particules/vapeurs (par exemple le trioxyde d'arsenic).

Zrak na delovnem mestu - Kovine in polkovine v lebdečih delcih - Zahteve za vrednotenje merilnih postopkov (ISO 21832:2018)

General Information

• Status: Published
• Publication Date: 07-Apr-2020
• Withdrawal Date: 30-Oct-2020
• ICS: 13.040.30 - Workplace atmospheres
• Technical Committee: CEN/TC 137 - Assessment of workplace exposure
• Drafting Committee: CEN/TC 137/WG 2 - General requirements for measuring procedures
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 08-Apr-2020
• Due Date: 12-Sep-2021
• Completion Date: 08-Apr-2020
• Ref Project: SIST EN ISO 21832:2020 - Workplace air - Metals and metalloids in airborne particles - Requirements for evaluation of measuring procedures (ISO 21832:2018)

Relations

• Replaces: EN 13890:2009 - Workplace exposure - Procedures for measuring metals and metalloids in airborne particles - Requirements and test methods
• Effective Date: 08-Jun-2022

Overview

EN ISO 21832:2020 - Workplace air - Metals and metalloids in airborne particles - sets out performance requirements and test methods for evaluating measuring procedures that determine metals and metalloids on collection substrates from workplace air. It provides a harmonized framework for method validation, including estimating and combining random and systematic uncertainties to calculate the expanded uncertainty of a complete measuring procedure in line with ISO 20581.

Key topics and requirements

• Scope and applicability

  • Applies to measuring procedures where sampling and analysis are separate stages (particle sampling onto a substrate followed by laboratory analysis).
  • Excludes measurement of metals/metalloids present as inorganic gases or vapours (e.g., gaseous mercury, arsenic vapour) and particle/vapour mixtures (e.g., arsenic trioxide).
  • Does not prescribe sample collection, transport or storage requirements (see EN 13205-1 and ISO 15767).

• Method performance requirements

  • Limit of quantification (LOQ) and instrumental detection limit (IDL) assessment.
  • Analytical recovery determination for soluble and total metal procedures, with guidance in Annex A.
  • Identification and estimation of random and non-random (systematic) uncertainty components and calculation of expanded uncertainty (detailed in Clause 8 and Annex C).
  • Tests and procedures for method validation, including experimental designs (Annex B) and worked examples (Annex E).

• Practical test elements

  • Requirements for method description, application range, safety, samplers, sampling pumps, reagents, standard solutions and apparatus.
  • Test methods for LOD/LOQ, recovery, and uncertainty estimation (including interpolation of standard deviation - Annex D).

Applications and who uses this standard

• Industrial hygienists and occupational health professionals validating workplace air monitoring procedures for metals and metalloids.
• Analytical laboratories developing or assessing analytical methods for airborne particulate metals.
• Regulatory bodies and safety agencies requiring documented method performance, traceability and uncertainty estimates for exposure assessment.
• Employers and industrial users implementing exposure monitoring programs and demonstrating compliance with occupational exposure limits.

Related standards

• ISO 20581 - General requirements for performance of procedures for measuring chemical agents in workplace atmospheres (uncertainty framework).
• EN 13205-1, ISO 15767 - Sample collection, transport and storage requirements for workplace air monitoring.

By following EN ISO 21832:2020, organizations can ensure robust method validation, reliable measurement uncertainty estimates, and consistent, comparable results when monitoring workplace airborne metals and metalloids.

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2020
Nadomešča:
SIST EN 13890:2009
Zrak na delovnem mestu - Kovine in polkovine v lebdečih delcih - Zahteve za
vrednotenje merilnih postopkov (ISO 21832:2018)
Workplace air - Metals and metalloids in airborne particles - Requirements for evaluation
of measuring procedures (ISO 21832:2018)
Luft am Arbeitsplatz - Metalle und Metalloide in luftgetragenen Partikeln - Anforderungen
an die Evaluation von Messverfahren (ISO 21832:2018)
Air des lieux de travail - Métaux et métalloïdes dans les particules en suspension dans
l'air - Exigences relatives à l'évaluation des procédures de mesure (ISO 21832:2018)
Ta slovenski standard je istoveten z: EN ISO 21832:2020
ICS:
13.040.30 Kakovost zraka na delovnem Workplace atmospheres
mestu
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21832
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2020
EUROPÄISCHE NORM
ICS 13.040.30 Supersedes EN 13890:2009
English Version
Workplace air - Metals and metalloids in airborne particles
- Requirements for evaluation of measuring procedures
(ISO 21832:2018)
Air des lieux de travail - Métaux et métalloïdes dans les Luft am Arbeitsplatz - Metalle und Metalloide in
particules en suspension dans l'air - Exigences luftgetragenen Partikeln - Anforderungen an die
relatives à l'évaluation des procédures de mesure (ISO Evaluation von Messverfahren (ISO 21832:2018)
21832:2018)
This European Standard was approved by CEN on 28 March 2020.

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, Turkey 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21832:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 21832:2018 has been prepared by Technical Committee ISO/TC 146 "Air quality” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 21832:2020 by
Technical Committee CEN/TC 137 “Assessment of workplace exposure to chemical and biological
agents” the secretariat of which is held by DIN.
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 October 2020, and conflicting national standards shall
be withdrawn at the latest by October 2020.
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 13890:2009.
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,
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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 21832:2018 has been approved by CEN as EN ISO 21832:2020 without any modification.

INTERNATIONAL ISO
STANDARD 21832
First edition
2018-11
Workplace air — Metals and
metalloids in airborne particles
— Requirements for evaluation of
measuring procedures
Air des lieux de travail — Métaux et métalloïdes dans les particules
en suspension dans l'air — Exigences relatives à l'évaluation des
procédures de mesure
Reference number
ISO 21832:2018(E)
©
ISO 2018
ISO 21832:2018(E)
© ISO 2018
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]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

ISO 21832:2018(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Requirements . 3
5.1 Method description . 3
5.1.1 Application range . 3
5.1.2 Method performance . . . 3
5.1.3 Safety information . 3
5.1.4 Samplers. 3
5.1.5 Sampling pumps . 4
5.1.6 Other requirements . 4
5.2 Performance requirements . 4
5.2.1 Limit of quantification (LOQ) . 4
5.2.2 Analytical recovery . 4
5.2.3 Expanded uncertainty . 4
6 Reagents and materials . 5
6.1 Reagents. 5
6.2 Standard solutions . 5
6.3 Test materials . 5
6.4 Reference air samples . 5
7 Apparatus . 5
8 Test methods . 6
8.1 LOD and LOQ . 6
8.1.1 Instrumental detection limit (IDL). 6
8.1.2 Method LOD and LOQ . 6
8.2 Analytical recovery . 6
8.2.1 General. 6
8.2.2 Measuring procedures for soluble compounds of metals and metalloids . 7
8.2.3 Measuring procedures for total metals and metalloids that involve sample
dissolution . 7
8.2.4 Measuring procedures that do not involve sample dissolution . 8
8.3 Measurement uncertainty . 8
8.3.1 Identification of random and non-random uncertainty components . 8
8.3.2 Estimation of individual uncertainty components . 8
8.3.3 Calculation of expanded uncertainty . 9
9 Test report . 9
Annex A (informative) Guidance on determination of analytical recovery .11
Annex B (informative) Experiments for method validation .13
Annex C (informative) Estimation of uncertainty of measurement .14
Annex D (informative) Interpolation of standard deviation.30
Annex E (informative) Example for estimation of expanded uncertainty .32
Bibliography .36
ISO 21832:2018(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.
iv © ISO 2018 – All rights reserved

ISO 21832:2018(E)
Introduction
The health of workers in many industries is at risk through exposure by inhalation of toxic metals
and metalloids. Industrial hygienists and other public health professionals need to determine the
effectiveness of measures taken to control workers’ exposure, and this is generally achieved by taking
workplace air measurements. This document has been published in order to make available a method
for making valid ultra-trace exposure measurements for a wide range of metals and metalloids in use in
industry. It is intended for: agencies concerned with health and safety at work; industrial hygienists and
other public health professionals; analytical laboratories; and industrial users of metals and metalloids
and their workers.
This document provides a framework for assessing the performance of procedures for measuring metals
and metalloids against the general requirements for the performance of procedures for measuring
chemical agents in workplace atmospheres as specified in ISO 20581. It enables producers and users of
procedures for measuring metals and metalloids in airborne particles to adopt a consistent approach to
method validation. See also Annex B.
Although this document has been written for assessing the performance of procedures for measuring
metals and metalloids, it can be used as the basis for assessing the performance of procedures for
measuring other chemical agents that are present as or in airborne particles, for example, sulphuric
acid mist.
[14]
This document is based on EN 13890:2009 , published by the European Committee for
Standardization (CEN).
INTERNATIONAL STANDARD ISO 21832:2018(E)
Workplace air — Metals and metalloids in airborne
particles — Requirements for evaluation of measuring
procedures
1 Scope
This document specifies performance requirements and test methods for the evaluation of procedures
for measuring metals and metalloids in airborne particles sampled onto a suitable collection substrate.
This document specifies a method for estimating the uncertainties associated with random and
systematic errors and combining them to calculate the expanded uncertainty of the measuring
procedure as a whole, as prescribed in ISO 20581.
This document is applicable to measuring procedures in which sampling and analysis is carried out in
separate stages, but it does not specify performance requirements for collection, transport and storage
of samples, since these are addressed in EN 13205-1 and ISO 15767.
This document does not apply to procedures for measuring metals or metalloids present as inorganic
gases or vapours (e.g. mercury, arsenic) or to procedures for measuring metals and metalloids in
compounds that could be present as a particle/vapour mixture (e.g. arsenic trioxide).
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 3696, Water for analytical laboratory use — Specification and test methods
ISO 7708, Air quality — Particle size fraction definitions for health-related sampling
ISO 13137, Workplace atmospheres — Pumps for personal sampling of chemical and biological agents —
Requirements and test methods
ISO 18158, Workplace air — Terminology
ISO 20581:2016, Workplace air — General requirements for the performance of procedures for the
measurement of chemical agents
EN 13205-1, Workplace exposure — Assessment of sampler performance for measurement of airborne
particle concentrations — Part 1: General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 18158 and the following 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 21832:2018(E)
3.1
test sample
sample prepared to meet all specific conditions for a test
[SOURCE: ISO 11323:2010, 5.6]
3.2
test solution
solution prepared by the process of sample dissolution and, if necessary, having been subjected to any
further operations required to bring it into a state in which it is ready for analysis
[SOURCE: ISO 8518:2001, 3.4.4]
4 Principle
For measuring procedures that involve sample dissolution, instrumental detection limits (IDLs) are
determined by repeat analysis of blank solutions. For all measuring procedures, limits of detection
(LOD) and limits of quantification (LOQ) are determined by analysis of laboratory blanks. Typically, the
LOD and LOQ are calculated as three times and ten times the standard deviation of blank measurements,
respectively. The determined LOQs are then assessed against the performance requirements specified
in 5.2.1. Refer to ISO 18158 for definitions of these terms.
Analytical recovery is determined by one of a number of different methods, depending upon the nature
of the measuring procedure under evaluation. The determined analytical recovery is then assessed
against the performance requirements specified in 5.2.2.
For measuring procedures for soluble compounds of metals and metalloids, analytical recovery is
determined by analysis of spiked laboratory blanks (except for procedures that incorporate a design-
based sample dissolution method, see A.1.1, for which it is taken to be 100 %).
For measuring procedures for total metals and metalloids that involve sample dissolution, analytical
recovery is determined by analysis of pure compounds, reference materials or reference air samples.
For measuring procedures for total metals and metalloids that involve analysis of the sample on the
collection substrate, analytical recovery is determined by analysis of reference air samples, by the
analysis of workplace air samples that are characterized by subsequent analysis using a reference
procedure or it is estimated from theory.
Measurement uncertainty is estimated using a structured approach. Firstly, a cause and effect diagram
is constructed to identify individual random and non-random uncertainty components of a measuring
procedure. After simplification to resolve any duplication, the resulting diagram is used to identify
components for which uncertainty estimates are required. Each of these uncertainty components is
then estimated or calculated from experimental data, combined to obtain an estimate of the uncertainty
of the measurement method as a whole and multiplied by an appropriate coverage factor to calculate
the expanded uncertainty of the method, following the guidance in Annex C. In accordance with 5.2.3,
the determined expanded uncertainty is then assessed against the general performance requirements
specified in ISO 20581.
NOTE For an example for calculation of expanded uncertainty, see Annex E.
2 © ISO 2018 – All rights reserved

ISO 21832:2018(E)
5 Requirements
5.1 Method description
5.1.1 Application range
The application range of the measuring procedure shall give, at minimum, information about the
following:
a) the metals and metalloids covered by the measuring procedure;
b) the analytical technique(s) used in the measuring procedure;
c) the range of concentrations of metals and metalloids in air for which the measuring procedure has
been shown to meet the acceptance criteria for expanded uncertainty prescribed in ISO 20581,
−3 −3
together with the associated recommended sampled air volume (e.g. 0,01 mg ⋅ m to 0,5 mg ⋅ m
for a sampled air volume of 960 l);
d) any form of the metals and metalloids for which the sample preparation method described is
known to be, or has been shown to be, ineffective;
e) any known interferences.
If there is no procedure for measuring a particular metal or metalloid that meets the requirements of
this document, a measuring procedure that gives a performance nearest to the specified requirements
should be used.
5.1.2 Method performance
For all metals and metalloids included in the application range of the method, the measuring procedure
shall give comprehensive information about method performance, including the following:
a) the LOQ and, if required, LODs of the measuring procedure;
b) the analytical recovery for all test materials for which the sample preparation method has been
shown to be effective;
c) all random and non-random uncertainty components of the measuring procedure, together with
their estimated or experimentally determined values, and the resulting expanded uncertainty;
d) full details of any known interferences, including suitable and sufficient information on how to
minimize their effects, if applicable.
5.1.3 Safety information
The measuring procedure shall provide suitable and sufficient information on the safety hazards
associated with the reagents and equipment used in the procedure.
5.1.4 Samplers
The measuring procedure shall:
— require the user to select samplers that are designed to collect an appropriate fraction of airborne
particles, as defined in ISO 7708, according to the particle size fraction(s) that is(are) applicable to
the OELV for the metals and metalloids of interest (e.g. an inhalable sampler, a thoracic sampler or a
respirable sampler);
— specify that the samplers shall conform to the provisions of EN 13205-1;
ISO 21832:2018(E)
— require, if appropriate, for procedures that do not involve sample dissolution, that calibration of
the analytical instrument to be used [e.g. X-ray fluorescence (XRF) spectrometry] is specific to the
sampler to be used.
5.1.5 Sampling pumps
The measuring procedure shall require the user to use sampling pumps that conform to the provisions
of ISO 13137.
5.1.6 Other requirements
Where necessary, the measuring procedure shall give other requirements (e.g. for the collection
substrate).
5.2 Performance requirements
5.2.1 Limit of quantification (LOQ)
For each metal and metalloid included in the application range of the measuring procedure, the lower
limit of the working range of the method that will be satisfactory for the intended measurement task
shall be determined. For example, if the measurement task is testing compliance with long-term OELVs,
Formula (1) is used to calculate the least amount of the metal or metalloid that needs to be quantified
when it is to be determined at a concentration of 0,1 times its OELV:
mq=⋅01, ρ ⋅t (1)
lowLVv,,as min
where
m is the lower limit of the required analytical range of the metal or metalloid, in micrograms;
low
ρ is the OELV for the metal or metalloid, in milligrams per cubic metre;
LV
q is the design flow rate of the sampler to be used, in litres per minute;
v,a
t is the minimum sampling time that will be used, in minutes.
s,min
For procedures that involve sample dissolution, the lower limit of the required working range is
calculated for each metal and metalloid, in micrograms per millilitre, by dividing the lower limit of the
required working range, in micrograms, by the volume of the test solution, in millilitres. When tested in
accordance with 8.1.2.1, the determined LOQs shall be lower than the resulting values.
For procedures that do not involve sample dissolution, when tested in accordance with 8.1.2.2, the
determined LOQs for each metal and metalloid shall be lower than the lower limit of the required
working range in micrograms.
5.2.2 Analytical recovery
When tested in accordance with one of the procedures prescribed in 8.2, the mean analytical recovery
shall be at least 90 % for all material types included within the application range of the measuring
procedure and the coefficient of variation of the analytical recovery shall be less than 5 %.
NOTE The predecessor term to “coefficient of variation” is “relative standard deviation”, which is deprecated.
[1]
See also ISO 3534-1:2006, 2.38, Note 2 to entry .
5.2.3 Expanded uncertainty
The expanded uncertainty of the measuring procedure shall conform to the requirements specified in
ISO 20581.
4 © ISO 2018 – All rights reserved

ISO 21832:2018(E)
6 Reagents and materials
6.1 Reagents
During the analysis, only reagents of analytical grade, and only water conforming to the requirements
−1
for ISO 3696 grade 2 water (electrical conductivity less than 0,1 mS ⋅ m , i.e. resistivity greater than
0,01 MΩ ⋅ m, at 25 °C) may be used.
The water used should be obtained from a water purification system that delivers ultrapure water
having a resistivity greater than 0,18 MΩ ⋅ m (usually expressed by manufacturers of water purification
systems as 18 MΩ ⋅ cm water).
6.2 Standard solutions
Standard solutions with concentrations of the metals and metalloids of interest that are traceable to
national and/or international standards shall be used.
If commercial standard solutions are used, the manufacturer’s expiry date or recommended shelf life
shall be observed.
6.3 Test materials
For each metal or metalloid, a range of test materials shall be used that is representative of the
substances of interest that could be present in the workplace atmosphere.
The test materials shall be pure compounds of known composition, certified reference materials (CRMs)
or other well-characterized materials (e.g. materials characterized in an interlaboratory comparison).
When using CRMs, the supplier’s instructions shall be followed.
If there is an OELV for a specific compound, that compound should be included in the range of reference
materials.
For a method that is intended to have general applicability, the range of reference materials should
include compounds and materials in industrial use and compounds and materials that could be
generated by the work activity.
NOTE 1 It is important that the particle size of the reference materials be as close as possible to that of the
particles analysed, since, compared to coarse bulk materials, inhalable particles are often much smaller and
more readily soluble.
NOTE 2 CRMs that have been characterized with respect to a particular sample dissolution method might not
be suitable for use as a test material.
6.4 Reference air samples
Samples of dust on collection substrates (e.g. airborne particles collected on filters using a multiple
simultaneous sample collection system) having a known or measured loading of the metal or metalloid
of interest shall be used. The loading should be within the working range of the method.
Special techniques for the preparation of reference air samples, as described in A.3, should be considered
when sample dissolution is not required.
7 Apparatus
Usual laboratory apparatus and resources and, in particular, the following test equipment.
7.1 A system for applying a known volume of standard solution to collection substrates with a
precision of better than 1 %.
ISO 21832:2018(E)
7.2 An analytical balance capable of weighing to at least 0,01 mg, calibrated with weights traceable
to national standards, checked before use by means of a test weight.
7.3 An instrument or instruments for analysing each metal or metalloid of interest.
8 Test methods
8.1 LOD and LOQ
8.1.1 Instrumental detection limit (IDL)
For measuring procedures that involve sample dissolution, analyse the calibration blank solution at
least ten times under repeatability conditions.
If there is no measurable response from the analytical instrument, prepare a test solution with
concentrations of the metals or metalloids of interest near their anticipated instrumental limits of
detection by diluting the standard solutions (6.2) by an appropriate factor. Analyse the test solution at
least ten times under repeatability conditions.
NOTE An IDL is of use in identifying changes in instrument performance, but it is not the same as a
method LOD. An IDL is likely to be lower than a method LOD because it only takes into account the variability
between individual instrumental readings; determinations made on one solution do not take into consideration
contributions to variability from the matrix or sample.
8.1.2 Method LOD and LOQ
8.1.2.1 For measuring procedures that involve sample dissolution, prepare at least 10 test solutions
from laboratory blanks, following the sample preparation method described in the measuring procedure,
and analyse the test solutions for the metals or metalloids of interest under repeatability conditions.
If there is no measurable response from the analytical instrument, spike 10 laboratory blanks with an
appropriate volume of working standard solution containing appropriate known masses of the metals
or metalloids of interest, such that the test solutions produced from them will have concentrations near
their respective anticipated LODs. Prepare test solutions from the spiked laboratory blanks, following
the sample preparation method described in the measuring procedure, and analyse the test solutions
for the metals or metalloids of interest under repeatability conditions.
Calculate the method LOD and the LOQ for each metal or metalloid of interest as three times and ten
[22]
times the standard deviation, respectively .
8.1.2.2 For measuring procedures that do not involve sample dissolution, analyse at least 10 laboratory
blanks under repeatability conditions.
Calculate the method LOD and the LOQ for each metal or metalloid of interest as three times and ten
times the standard deviation, respectively.
8.1.2.3 Compare the LOQs obtained with the requirements of 5.2.1.
8.2 Analytical recovery
8.2.1 General
Different test methods are applicable for the determination of analytical recovery, depending on the
sample preparation method used. These are detailed separately in 8.2.2, 8.2.3 and 8.2.4. See Annex A
for guidance.
6 © ISO 2018 – All rights reserved

ISO 21832:2018(E)
8.2.2 Measuring procedures for soluble compounds of metals and metalloids
8.2.2.1 Measuring procedures that incorporate a design-based sample dissolution method
Unless there is a contra-indication (see A.1.2), take the analytical recovery to be 100 % for procedures
for soluble compounds of metals and metalloids that incorporate a design-based sample dissolution
method (see A.1.1).
8.2.2.2 Other measuring procedures
For measuring procedures that do not incorporate a design-based sample dissolution method or for
which there could be a problem of chemical compatibility between the analyte and the substrate,
prepare a minimum of six replicate test samples by spiking laboratory blanks with an appropriate
volume of working standard solution containing a known mass of each metal or metalloid of interest.
Then use the sample dissolution method described in the measuring procedure to prepare test solutions
from the test samples and analyse the resulting solutions using the analytical method described in the
measuring procedure.
Repeat the test on laboratory blanks spiked with other masses of each metal or metalloid of interest to
determine the analytical recovery across the working range of the measuring procedure.
Calculate the mean analytical recovery and coefficient of variation for each of the tests performed and
compare the results with the requirements of 5.2.2. If the requirements are not met, take corrective
measures (e.g. use an alternative collection substrate), if possible, and repeat the analytical recovery test.
8.2.3 Measuring procedures for total metals and metalloids that involve sample dissolution
8.2.3.1 Determination of analytical recovery using pure compounds
Prepare a minimum of six test solutions from each of the selected pure compounds (6.3) using the
sample preparation method described in the measuring procedure. Use a mass of the pure compound
that can be weighed with an accuracy of at least 1 %. Analyse the test solutions as described in the
measuring procedure.
NOTE It is usually not necessary to include water-soluble compounds in the range of compounds tested.
It is preferable to use the smallest mass of pure compound that can be easily weighed, to scale up the
volume of reagents and to adjust the final test solution volume so that the experiment is as representative
as possible of the analysis of workplace air samples.
8.2.3.2 Determination of analytical recovery using reference materials
Carry out the same test procedure prescribed for pure compounds in 8.2.3.1. Use a suitable mass of each
of the selected reference materials (6.3), taking into consideration the concentration of each metal or
metalloid of interest in the reference material and the supplier’s instructions on the minimum amount
of material that is required for a homogenous sample.
It is preferable to use the smallest mass of reference material that can be easily weighed, to scale
up the volume of reagents and to adjust the final test solution volume so that the experiment is as
representative as possible of the analysis of workplace air samples.
8.2.3.3 Determination of analytical recovery using reference air samples
Prepare and analyse test solutions from a minimum of six reference air samples (6.4) using the method
described in the measuring procedure.
ISO 21832:2018(E)
8.2.3.4 Comparison of results with the acceptance criteria
Calculate the mean analytical recovery and coefficient of variation for each of the tests performed and
compare the results with the requirements of 5.2.2. If the requirements are not met for a test material,
the analytical recovery test may be repeated using material with a smaller particle size and/or using
a larger volume of reagents. If the requirements are still not met, the materials of a type similar to the
test material concerned shall be excluded from the scope of the measuring procedure.
8.2.4 Measuring procedures that do not involve sample dissolution
8.2.4.1 Experimental determination of analytical recovery
8.2.4.1.1 Reference air samples
Analyse a minimum of six reference air samples (6.4) using the method described in the measuring
procedure.
8.2.4.1.2 Workplace air samples
Analyse a minimum of six workplace air samples using the method described in the measuring
procedure. Then re-analyse the samples using an independent measuring procedure with known
analytical recovery to obtain reference values for each metal or metalloid of interest.
8.2.4.1.3 Comparison of results with the acceptance criteria
Calculate the mean analytical recovery and coefficient of variation for each of the tests performed and
compare the results with the requirements of 5.2.2. If the requirements are not met, ensure that the
limitations of the measuring procedure are fully described in its application range.
8.2.4.2 Theoretical estimation of analytical recovery
Estimate the analytical recovery by theoretical consideration of the principles of the technique involved
and compare results with the analytical recovery requirements of 5.2.2.
NOTE For example, the maximum sample loading for quantitative determination of metals and metalloids in
[20]
air by X-ray fluorescence spectrometry can be estimated from theory .
8.3 Measurement uncertainty
8.3.1 Identification of random and non-random uncertainty components
See Table B.1 for a list of random and non-random uncertainty components that typically should be
considered.
8.3.2 Estimation of individual uncertainty components
8.3.2.1 General
For each of the significant uncertainty components identified in 8.3.1, estimate individual uncertainties
or calculate them from experimental data as prescribed in 8.3.2.2 to 8.3.2.6, following the guidance
given in Annex C.
Where appropriate, convert a range ± A, into a non-random uncertainty equal to A 3 , assuming a
rectangular probability distribution or into a non-random uncertainty equal to A 6 , assuming a
triangular probability distribution, as appropriate.
8 © ISO 2018 – All rights reserved

ISO 21832:2018(E)
8.3.2.2 Uncertainty associated with sampled air volume
Estimate the random and non-random uncertainty components of the sampled air volume, referring to
the guidance in C.2.
If the measurement uncertainty is being estimated for the general use of a published method, make a
worst-case estimate of the uncertainty components concerned.
If the measurement uncertainty is being estimated for the use of the method under specific conditions
(e.g. by a particular organization using particular sampling equipment and a particular sampling
protocol), estimate the uncertainty components for the specific equipment concerned (e.g. flow meter,
sampling pump, timer), taking account of any specific additional requirements of the sampling protocol
(e.g. number of flow rate measurements, sampling time).
8.3.2.3 Uncertainty associated with sampling efficiency
Estimate the random and non-random uncertainty components for aerosol samplers referring to the
guidance in C.3.
8.3.2.4 Uncertainty associated with sample storage and transportation
Estimate the non-random uncertainty components associated with sample storage and transportation,
referring to the guidance in C.4.
8.3.2.5 Uncertainty associated with analytical recovery
Estimate analytical recovery and the non-random uncertainty components associated with analytical
bias, referring to the guidance in C.5.
8.3.2.6 Uncertainty associated with analytical variability
Estimate the random uncertainty components associated with analytical variability referring to the
guidance in C.6.
8.3.3 Calculation of expanded uncertainty
Calculate the expanded uncertainty of the measuring procedure by combining the random and non-
random components of sampling uncertainty and analytical uncertainty (see C.7.1, C.7.2 and C.7.3) and
multiplying by a coverage factor of two (see C.8).
9 Test report
The test report shall include at least the following:
a) a reference to this document, i.e. ISO 21832;
b) identification of the test laboratory, including brief information concerning any relevant
accreditation;
c) identification of the procedure tested;
d) information about the sampling equipment for which the performance of procedure was assessed;
e) information about the reference materials used and, for reference air samples, how they were
prepared;
f) a brief description of the analytical method tested, including information about the analytical
instruments used;
g) information about which of the test methods prescribed in Clause 8 were followed;
ISO 21832:2018(E)
h) a list of the metals and/or metalloids evaluated;
i) information about any operation not included in this document that
...