EN ISO 15796:2008

SLOVENSKI STANDARD
01-oktober-2008
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Gas analysis - Investigation and treatment of analytical bias (ISO 15796:2005)
Gasanalyse - Untersuchung und Behandlung von systematischen Abweichungen (ISO
15796:2005)
Analyse des gaz - Investigation et traitement des biais analytiques (ISO 15796:2005)
Ta slovenski standard je istoveten z: EN ISO 15796:2008
ICS:
71.040.40 Kemijska analiza Chemical analysis
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 15796
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2008
ICS 71.040.40
English Version
Gas analysis - Investigation and treatment of analytical bias
(ISO 15796:2005)
Analyse des gaz - Investigation et traitement des biais Gasanalyse - Untersuchung und Behandlung von
analytiques (ISO 15796:2005) systematischen Abweichungen (ISO 15796:2005)
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.
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EUROPÄISCHES KOMITEE FÜR NORMUNG
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© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15796:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3

Foreword
The text of ISO 15796:2005 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 15796:2008 by
Technical Committee CEN/SS 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 15796:2005 has been approved by CEN as a EN ISO 15796:2008 without any modification.

INTERNATIONAL ISO
STANDARD 15796
First edition
2005-03-01
Gas analysis — Investigation and
treatment of analytical bias
Analyse des gaz — Investigation et traitement des biais analytiques

Reference number
ISO 15796:2005(E)
©
ISO 2005
ISO 15796:2005(E)
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ii © ISO 2005 – All rights reserved

ISO 15796:2005(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Terms and definitions. 1
3 Symbols. 3
4 Bias related to instrumental drift. 4
4.1 Principle. 4
4.2 Stability monitoring. 4
4.3 Drift correction. 6
5 Bias related to effects of sample composition . 10
5.1 Principles. 10
5.2 Local bias handling. 11
5.3 Bias handling for an extended measuring range . 23
6 Treatment of matrix interferences. 27
Annex A (normative)  Critical values for the trend test . 29
Annex B (informative) Uncertainty issues . 30
Bibliography . 33

ISO 15796:2005(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 15796 was prepared by Technical Committee ISO/TC 158, Analysis of gases.

iv © ISO 2005 – All rights reserved

ISO 15796:2005(E)
Introduction
Traceability is considered as one of the key items of quality assurance in gas analysis. In general, it is defined
by the existence of unbroken chains of comparisons, relating the analytical result to acknowledged standards
of measurement. More specifically, an analytical result is considered traceable if, by way of these
comparisons, it has been demonstrated to be free of significant bias, significance referring to the specified
uncertainty of the result.
As a rule, traceability is not demonstrated individually for a single analytical result but for a defined analytical
procedure with specified ranges of analyte concentration and matrix composition. An analytical procedure is
considered traceable if it has been demonstrated to be free of significant bias, or if significant bias has been
corrected, by measurement on representative samples of known traceable composition. These may be
samples of appropriate reference gas mixtures. Alternatively, other representative samples may be analysed
in parallel using an accepted reference procedure.
This International Standard provides generic methods for demonstrating, or establishing, traceability of
analytical procedures using reference gas mixtures or reference analytical procedures, implementing
[1] [2]
principles laid out in ISO 14111 and ISO/TS 14167 , and respecting the principles of the Guide to the
[3]
Expression of Uncertainty in Measurement (GUM) .
In this International Standard, the term “concentration” is used for two different purposes:
 as a general term for quantities measured in gas composition analysis, replacing the term “content” (see
[4]
ISO 7504 );
 as a generic substitute for any of the specific quantities measured in gas composition analysis such as
[4]
the mass concentration or the mole fraction of a specified analyte (see ISO 7504 ).

INTERNATIONAL STANDARD ISO 15796:2005(E)

Gas analysis — Investigation and treatment of analytical bias
1 Scope
This International Standard specifies generic methods for detecting and correcting bias (systematic errors) of
analytical procedures for the analysis of gases, using reference gas mixtures or reference analytical
procedures, as well as for estimating the correction uncertainty.
The main sources of (and parameters affecting) bias of analytical procedures are instrumental drift (time) and
matrix interferences (matrix composition). Moreover, bias normally varies with analyte concentration. This
International Standard therefore establishes protocols for
 detecting and correcting drift for an analytical system of limited stability,
 investigating and handling bias of a stable analytical system for a specified range of sample composition,
which are intended to be used in method development and method validation studies, either separately or
sequentially.
This International Standard specifies procedures for two options, applicable to systematic effects, as follows:
a) tracing the observed pattern of deviations and correcting for their effect,
b) averaging over their effects and increasing the uncertainty,
where normally the first option entails lower uncertainty at the expense of higher effort.
For the convenience of the user, the methods specified in this International Standard are described for
procedures of composition analysis, i.e. procedures for measuring the concentration of a specified analyte in a
gas mixture. However, they are equally applicable to measurements of physico-chemical properties of a gas
or gas mixture relevant to gas analysis, and translation into this subject field is straightforward.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
bias
estimate of systematic error
NOTE Since the true value of a measurand cannot be known exactly, systematic errors cannot be determined exactly
but have to be estimated using reference values.
2.2
correction
procedure by which the uncorrected result of a measurement is adjusted to compensate for systematic error
NOTE 1 Since systematic errors cannot be determined exactly, a correction can never be complete.
[5]
NOTE 2 In
...