SIST EN ISO 13162:2015

SLOVENSKI STANDARD
SIST EN ISO 13162:2015
01-oktober-2015
.DNRYRVWYRGH'RORþDQMHDNWLYQRVWLRJOMLND&0HWRGDãWHWMDVWHNRþLQVNLP
VFLQWLODWRUMHP,62
Water quality - Determination of carbon 14 activity -- Liquid scintillation counting method
(ISO 13162:2011)
Wasserbeschaffenheit - Bestimmung der Aktivität von Kohlenstoff-14 - Verfahren mit
dem Flüssigszintillationszähler (ISO 13162:2011)
Qualité de l'eau - Détermination de l'activité volumique du carbone 14 - Méthode par
comptage des scintillations en milieu liquide (ISO 13162:2011)
Ta slovenski standard je istoveten z: EN ISO 13162:2015
ICS:
13.060.60 Preiskava fizikalnih lastnosti Examination of physical
vode properties of water
17.240 Merjenje sevanja Radiation measurements
SIST EN ISO 13162:2015 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 13162:2015

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SIST EN ISO 13162:2015

EUROPEAN STANDARD
EN ISO 13162

NORME EUROPÉENNE

EUROPÄISCHE NORM
August 2015
ICS 17.240; 13.060.60
English Version
Water quality - Determination of carbon 14 activity - Liquid
scintillation counting method (ISO 13162:2011)
Qualité de l'eau - Détermination de l'activité volumique du Wasserbeschaffenheit - Bestimmung der Aktivität von
carbone 14 - Méthode par comptage des scintillations en Kohlenstoff-14 - Verfahren mit dem
milieu liquide (ISO 13162:2011) Flüssigszintillationszähler (ISO 13162:2011)
This European Standard was approved by CEN on 30 July 2015.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, 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: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13162:2015 E
worldwide for CEN national Members.

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SIST EN ISO 13162:2015
EN ISO 13162:2015 (E)
Contents
Page
European foreword .3
2

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SIST EN ISO 13162:2015
EN ISO 13162:2015 (E)
European foreword
The text of ISO 13162:2011 has been prepared by Technical Committee ISO/TC 147 “Water quality” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 13162:2015 by
Technical Committee CEN/TC 230 “Water analysis” 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 February 2016, and conflicting national standards shall be withdrawn
at the latest by February 2016.
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, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 13162:2011 has been approved by CEN as EN ISO 13162:2015 without any modification.

3

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SIST EN ISO 13162:2015

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SIST EN ISO 13162:2015
INTERNATIONAL ISO
STANDARD 13162
First edition
2011-11-01
Water quality — Determination of
carbon 14 activity — Liquid scintillation
counting method
Qualité de l’eau — Détermination de l’activité volumique du
carbone 14 — Méthode par comptage des scintillations en milieu liquide
Reference number
ISO 13162:2011(E)
©
ISO 2011

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SIST EN ISO 13162:2015
ISO 13162:2011(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2011 – All rights reserved

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SIST EN ISO 13162:2015
ISO 13162:2011(E)
Contents Page
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Symbols, definitions, units, and abbreviations . 2
4 Principle . 2
5 Reagents and equipment . 3
5.1 Reagents . 3
5.2 Equipment . 4
6 Sampling and samples . 5
6.1 Sampling . 5
6.2 Sample storage . 5
7 Procedure . 5
7.1 Sample preparation . 5
7.2 Preparation of the sources to be measured . 5
7.3 Counting procedure . 6
7.4 Calibration and verification . 6
7.5 Measurement conditions . 6
8 Expression of results . 7
8.1 General . 7
8.2 Calculation of activity concentration . 7
8.3 Decision threshold . 8
8.4 Detection limit . 8
8.5 Confidence limits . 9
8.6 Calculations using the activity per mass . 9
9 Test report . 9
Annex A (informative) Numerical applications . 11
Annex B (informative) Internal standard method .13
Annex C (informative) Extraction of total carbon: precipitate counting .15
Annex D (informative) Extraction of total carbon: absorption counting .18
Bibliography .21
© ISO 2011 – All rights reserved iii

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SIST EN ISO 13162:2015
ISO 13162:2011(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 13162 was prepared by Technical Committee ISO/TC 147, Water quality.
iv © ISO 2011 – All rights reserved

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SIST EN ISO 13162:2015
ISO 13162:2011(E)
Introduction
14
The carbon 14 ( C) present in the environment is of natural origin and man made. As a result of atmospheric
nuclear weapon testing, emissions from nuclear engineering installations, and the application and processing
14
of isotopes, relatively large amounts of C have been released into the environment. Due to the substantial
14 14
proportion of C in the human internal dose contribution, monitoring of C activity concentrations in the
14
environment is necessary in order to follow its circulation in the hydrosphere and biosphere. C is the second
40
radionuclide (�3 500 Bq) to contribute to the human body natural radioactivity, behind K (�6 000 Bq).
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SIST EN ISO 13162:2015

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SIST EN ISO 13162:2015
INTERNATIONAL STANDARD ISO 13162:2011(E)
Water quality — Determination of carbon 14 activity — Liquid
scintillation counting method
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This standard does not purport to address all of the safety problems, if any, associated with
its use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted according to this International Standard
be carried out by suitably trained staff.
1 Scope
14
This International Standard specifies the conditions for the determination of C activity concentration in
14
samples of environmental water or of C-containing water using liquid scintillation counting.
The method is applicable to the analysis of any organic molecule soluble in water that is well mixed with the
scintillation cocktail. It does not apply to micelles or “large” particles (lipids, fulvic acid, humic acid, etc.) that are
inadequately mixed with the scintillation cocktail and the water. Some beta energy is lost without any excitation
of the scintillation cocktail and the results are underestimated. The method is not applicable to the analysis
14
of organically bound C, whose determination requires additional chemical processing (such as chemical
oxidation, combustion).
14 6 �1
It is possible to determine C activity concentrations below 10 Bq l without any sample dilution.
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 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and
sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO 11929, Determination of the characteristic limits (decision threshold, detection limit and limits of the
confidence interval) for measurements of ionizing radiation — Fundamentals and application
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
ISO 80000-10, Quantities and units — Part 10: Atomic and nuclear physics
ISO/IEC Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
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SIST EN ISO 13162:2015
ISO 13162:2011(E)
3 Symbols, definitions, units, and abbreviations
For the purposes of this document, the symbols, definitions, units, and abbreviations defined in ISO 80000-10,
ISO 11929, ISO/IEC Guide 98-3 and the following apply.
� Activity of the calibration source, in becquerels
� Activity concentration, in becquerels per litre
�
*
Decision threshold, in becquerels per litre
c
A
�
Detection limit, in becquerels per litre
c
A

Lower and upper limits of the confidence interval, in becquerels per litre
cc�
AA
� Quench factor
q
�
Mass of test sample, in kilograms
� Background count rate, in reciprocal seconds
0
� Sample count rate, in reciprocal seconds
g
� Count rate of the calibration sample, in reciprocal seconds
s
� Background counting time, in seconds
0
� Sample counting time, in seconds
g
� Counting time of the calibration sample, in seconds
s
� Expanded uncertainty, calculated by � � ���(�) with � � 1, 2, …, in becquerels per litre
�
�(�) Standard uncertainty associated with the measurement result, in becquerels per litre
�
� Volume of test sample, in litres
� Activity per mass, in becquerels per kilogram
� Maximum energy for the beta emission, in kiloelectronvolts
max
� Detection efficiency
� Mass density of the sample, in kilograms per litre
4 Principle
The scintillation phenomenon results from interaction of ionizing radiation with solvents and compounds
exhibiting fluorescence (scintillators). Both solvents and scintillators constitute the scintillation cocktail. The
scintillation mixture is achieved by adding the scintillation cocktail to the test sample in order to obtain a
homogeneous mixture.
The test sample is mixed with the scintillation cocktail in a counting vial to obtain a homogeneous medium.
14
Electrons emitted by C transfer their energy to the scintillation medium. Molecules excited by this process
return to their ground state by emitting photons that are detected by photodetectors.
The electric pulses emitted by the photodetectors are amplified, sorted (in order to remove random events)
and analysed by the electronic systems and the data analysis software. The count rate of these electric pulses
allows the determination of the test sample activity, after correcting for the background count rate and detection
efficiency.
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SIST EN ISO 13162:2015
ISO 13162:2011(E)
In order to determine the background, a blank sample is prepared in the same way as the test sample. The
blank sample is prepared using a reference water of the lowest activity available, in accordance with the
activities to be measured.
The detection efficiency is determined with a calibration sample that is prepared with a standard of aqueous
14
C, or a dilution of this standard with reference water, measured under the same conditions as the test sample.
The sample (blank, test, calibration) and the measurement conditions shall be:
— same type of counting vial;
— same filling geometry;
— same scintillation cocktail;
— same ratio between test sample and scintillation cocktail;
— temperature stability of the detection apparatus;
— value of quench-indicating parameter included in calibration curve.
14
A prerequisite for the direct determination of C in a water sample is the absence of or a negligible contribution
90
from other beta-emitting radionuclides, such as Sr and Ra isotopes. When the radionuclide content of the
14
sample is unknown, the method specified in this International Standard only provides a C equivalent activity
for the sample.
Examples of methods of sample pretreatment are described in Annexes C and D.
Concerning quench correction, if particular conditions of chemical quenching affect the measurement results,
it is recommended that a quench curve be established. It is important to choose the chemical quenching agent
in accordance with the supposed type of quenching observed in the sample.
5 Reagents and equipment
5.1 Reagents
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade.
5.1.1 Reference water for the blank
The reference water for the blank should be as free as possible of chemical or radioactive impurities.
14
The reference water may have a low C activity concentration, in becquerels per litre, at the time � at which
the samples are measured.
14
For example, obtain water with a C activity concentration as low as possible, e.g. (deep) subterranean water.
Distil the water. Keep the distillate in a well-sealed borosilicate glass bottle in the dark at a temperature as
14
constant as possible; this reference water shall be kept physically remote from any C-containing material
14
(see next paragraph). Determine (see final paragraph) the C activity concentration (� � 0), in becquerels per
litre, of this water and note the date (� � 0) of this determination.
It is advisable to keep an adequate quantity of reference water in stock and to draw off small working volumes
14
from it for immediate use, as required. Contamination with C (e.g. from CO in the air) or other radioactive
2
species should be avoided.
�1
For measurement of activity concentrations close to 1 Bq l , water with a very low activity concentration is
necessary as reference water.
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SIST EN ISO 13162:2015
ISO 13162:2011(E)
5.1.2 Calibration source solution
In order to avoid cross-contamination, prepare the calibration source solution in a suitable location which is
14
remote from the area where the C analyses are to be carried out. Weigh and pour the requisite quantity
14 14
of a C aqueous standard solution into a weighed volumetric flask (e.g. of capacity 100 ml), so that the C
activity concentration generates sufficient counts to reach the required measurement uncertainty after dilution
14
with water for the blank and thorough mixing. Calculate the C activity concentration of the resulting internal
standard solution (� � 0), in becquerels per litre. Note the date at which the standard solution was made up
(� � 0).
5.1.3 Scintillation solution
The scintillation cocktail is chosen according to the characteristics of the sample to be analysed and according
to the properties of the detection apparatus.
It is recommended that a good hydrophilic scintillation cocktail be used, especially for the measurement of low
activity levels.
The scintillation cocktail shall be homogeneous and stable.
For the measurement of raw waters containing particles in suspension, it is recommended that a scintillation
cocktail leading to a gel-type mixture for the added volume of water be used.
It is recommended that the scintillation solution be:
— stored in the dark and, particularly just before use, exposure to direct sunlight or fluorescent light avoided
in order to prevent interfering luminescence;
— compliant with the storage conditions specified by the scintillation cocktail supplier.
The mixtures (scintillation cocktail and test sample) should be disposed of as chemical waste, and, depending
on the radioactivity, may require disposal as radioactive waste.
5.1.4 Quenching agent
Examples of chemical quenching agents (non acid): organochloride compounds, nitromethane.
NOTE Some quenching agents are dangerous or toxic.
5.2 Equipment
Usual laboratory equipment and in particular the following.
5.2.1 Liquid scintillation counter, preferably with an automatic sample transfer and ability to measure or
correct for sample quench.
Operation at constant temperature is recommended. Follow the manufacturer’s instructions.
The method specified in this International Standard relates to the widely used liquid scintillation counters
(LSCs) with vials that hold about 20 ml. When other vials are used with appropriate counters, the method
specified shall be adapted accordingly.
5.2.2 Pipette, suitable for
— accurate transfer of the standard solution (e.g. a micropipette of capacity 100 µl);
— accurate transfer of the test sample.
5.2.3 Balance, e.g. capable of being read to the nearest 0,1 mg.
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SIST EN ISO 13162:2015
ISO 13162:2011(E)
5.2.4 Counting vials.
Different types of scintillation vials exist, manufactured using a range of materials. The most common are glass
vials and polyethylene (PE) vials. Glass vials allow visual inspection of the scintillation medium, but have an
40
inherent background, due to the presence of K. However, some organic solvents contained in scintillation
cocktails diffuse through PE, accelerating the degradation of the mixture.
There are other types of vials.
40
— Glass vials with low level of K, which exhibit a lower background than “normal” glass vials.
— Polytetrafluoroethylene vials (PTFE) or PE vials with a layer of PTFE on the inside wall, which are strongly
14
recommended for the determination of very low C concentrations. Diffusion of organic solvents is slower
through PTFE than through PE. These vials are used for long counting times when very low-level activity
is to be measured.
Generally, the vials are single use. If the vial is re-used, efficient cleaning is essential.
To prevent interfering luminescence, counting vials should be kept in the dark and should not be exposed to
direct sunlight or fluorescent light, particularly just before use.
NOTE Toluene-based scintillation solutions can physically distort PE and counting vials made of that polymer are
unsuitable for use with them. Diffusion of organic solvents into and through the walls is also a serious drawback of PE vials.
6 Sampling and samples
6.1 Sampling
Conditions of sampling shall conform to ISO 5667-1 and ISO 5667-3.
2� �
The samples shall not be acidified to avoid the destruction of the carbonic equilibrium (CO , HCO , H CO ),
2 3
3 3
as specified in ISO 5667-3.
It is important that the laboratory receives a representative sample, unmodified during transport or storage and
in an undamaged container. It is recommended that a glass flask filled to the maximum be used to minimize
14
C exchange with atmospheric CO .
2
For low level activity measurements, it is important to avoid any contact between sample and atmosphere
during the sampling.
6.2 Sample storage
If required, the sample shall be stored in compliance with ISO 5667-3 for carbon dioxide. If the storage duration
exceeds that specified in ISO 5667-3, it is advisable to store the samples in glass flasks.
7 Procedure
7.1 Sample preparation
On a raw sample, measurement of the test sample is generally performed without removal of suspended
matter, if the sample has low levels of such material. If the activity of a filtered or centrifuged sample is to be
measured, the removal of suspended matter shall be performed as soon as possible after sampling.
7.2 Preparation of the sources to be measured
Known quantities of test sample and scintillation cocktail are introduced into the counting vial.
After closing the vial, it shall be thoroughly shaken to homogenize the mixture.
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SIST EN ISO 13162:2015
ISO 13162:2011(E)
The vial identification shall be written on the top of the vial stopper. The storage time depends upon the
scintillation mixture, the mixture stability and the nature of the sample. It is recommended that the measurement
be performed as soon as any photoluminescence or static electricity effects have become negligible (e.g. 12 h).
In order to reduce photoluminescence effects, it is recommended that the above mentioned operations take
place in dimmed light (preferably light from an incandescent source or red light); in addition, exposure of the
vial to direct sunlight or fluorescent light should be avoided.
7.3 Counting procedure
The test sample and background measurement conditions (measurement time, number of cycles or repetitions)
are defined according to the uncertainty and detection limit to be achieved.
7.4 Calibration and verification
Statistical control of the detection system shall be monitored by measurement of the reference vials (background,
14 [1]
tritium and C) usually provided by the equipment supplier, e.g. in compliance with ISO 8258 .
The measurement of the blank sample is performed before each test or each series of sample tests under
conditions representative of each type of measurement (Clause 4).
It is essential to generate a quench curve for each type of matrix measured. The quench curve is valid only for:
a) a given type of measurement apparatus;
b) a given type of scintillation cocktail;
c) a given ratio of scintillation cocktail and test sample;
d) a given energy window;
14
e) a given analyte radionuclide, e.g. C.
The quench curve is obtained with a series (e.g. 10) of working standards, presenting different quench. The
matrix of the working standards is representative of matrix of the samples to be measured (same scintillation
liquid, same ratio scintillation liquid-test sample). The working standards may be prepared as follows:
14
— similar quantity of C standard water solution in each vial. The activity of the certified standard shall be
sufficient for the counting ratio to be defined with a known statistical precision, even in the case of a strong
quench;
— the standard is completed with reference water until the volume of test sample is reached;
— the scintillation cocktail is added to obtain the desired ratio;
— one working standar
...