EN ISO 22125-2:2019

Water quality - Technetium-99 - Part 2: Test method using inductively coupled plasma mass spectrometry (ICP-MS) (ISO 22125-2:2019)

This document specifies a method for the measurement of 99Tc in all types of water by inductively coupled plasma mass spectrometry (ICP-MS).
The method is applicable to test samples of supply/drinking water, rainwater, surface and ground water, as well as cooling water, industrial water, domestic, and industrial wastewater after proper sampling and handling and test sample preparation. A filtration of the test sample is necessary.
The detection limit depends on the sample volume and the instrument used. The method described in this document, using currently available ICP-MS, has a detection limit of approximately 0,2 ng·kg−1 to 0,5 ng·kg−1 (0,1 Bq·kg−1 to 0,3 Bq·kg−1), which is much lower than the WHO criteria for safe consumption of drinking water (100 Bq·l−1)[3]. The method presented in this document is not intended for the determination of ultra-trace amount of 99Tc.
The mass concentration values in this document are expressed by sample mass unit instead of sample volume unit as it is usually the case in similar standards. The reason is that 99Tc is measured in various matrix types such as fresh water or sea water, which have significant differences in density. The mass concentration values can be easily converted to sample volume unit by measuring the sample volume. However, it increases the uncertainty on the mass concentration result.
The method described in this document is applicable in the event of an emergency situation, but not if 99mTc is present at quantities that could cause interference.
The analysis of Tc adsorbed to suspended matter is not covered by this method.
It is the user's responsibility to ensure the validity of this test method for the water samples tested.

Wasserbeschaffenheit - Technetium 99 - Teil 2: Verfahrens mittels Massenspektronomie und induktiv gekoppeltem Plasma (ICP-MS) (ISO 22125-2:2019)

Dieses Dokument legt ein Verfahren zur Messung von 99Tc in allen Wasserarten durch Massenspektrometrie mit induktiv gekoppeltem Plasma (ICP MS, en: inductively coupled plasma mass spectrometry) fest.
Das Verfahren ist auf Untersuchungsproben von Versorgungs /Trinkwasser, Regenwasser, Oberflächen  und Grundwasser sowie Kühlwasser, Prozesswasser, häusliches und gewerbliches Abwasser nach geeigneter Probenahme, Probenbehandlung und Vorbereitung der Untersuchungsprobe anwendbar. Es ist eine Filtration der Untersuchungsprobe notwendig.
Die Nachweisgrenze hängt vom Probenvolumen und dem verwendeten Gerät ab. Das in diesem Dokument beschriebene Verfahren hat, bei Verwendung derzeit verfügbarer ICP MS Geräte, eine Nachweisgrenze von etwa 0,2 ng · kg−1 bis 0,5 ng · kg−1 (entsprechend 0,1 Bq · kg−1 bis 0,3 Bq · kg−1); dies liegt unter den WHO Kriterien für den sicheren Verzehr von Trinkwasser (100 Bq · l−1) [3]. Das in diesem Dokument beschriebene Verfahren ist nicht für die Bestimmung von 99Tc im Ultraspurenbereich vorgesehen.
In diesem Dokument werden die Massenkonzentrationswerte bezogen auf die Masseneinheit statt auf die Volumeneinheit der Probe ausgedrückt, wie dies üblicherweise bei vergleichbaren Standards der Fall ist. Der Grund dafür ist, dass 99Tc in verschiedenen Matrixtypen wie Süßwasser oder Meerwasser gemessen wird, die hinsichtlich der Dichte signifikant unterschiedlich sind. Durch Messen des Probenvolumens können die Massenkonzentrationswerte auf einfache Weise auf die Volumeneinheit der Probe bezogen umgerechnet werden. Dies führt allerdings zur Erhöhung der Messunsicherheit des Massenkonzentrationsergebnisses.
Das in diesem Dokument beschriebene Verfahren ist bei Notfallsituationen anwendbar; dies gilt jedoch nicht, wenn 99mTc in Mengen vorhanden ist, die eine Interferenz verursachen könnten.
Die Analyse von Tc, das an Schwebstoffen adsorbiert ist, wird nicht durch dieses Verfahren abgedeckt.
Es liegt in der Verantwortung des Anwenders, die Validität dieses Prüfverfahrens für die zu prüfenden Wasserproben sicherzustellen.

Qualité de l'eau - Technétium-99 - Partie 2: Méthode d’essai par spectrométrie de masse couplée à un plasma induit (ISO 22125-2:2019)

Le présent document spécifie une méthode de mesure de 99Tc dans tous les types d'eau par spectrométrie de masse couplée à un plasma induit (ICP-MS).
Cette méthode est applicable aux échantillons pour essai d'eau de distribution/potable, d'eau pluviale, d'eau de surface et souterraine, ainsi que d'eau de refroidissement, d'eau industrielle, d'eau usée domestique et industrielle après échantillonnage, manipulation de l'échantillon et préparation de l'échantillon pour essai. Il est nécessaire de filtrer l'échantillon pour essai.
La limite de détection dépend du volume d'échantillon et de l'instrument utilisé. La méthode décrite dans le présent document, qui a recours aux spectromètres ICP-MS actuellement disponibles, a une limite de détection d'environ 0,2 ng·kg−1 à 0,5 ng·kg−1 (0,1 Bq·kg−1 à 0,3 Bq·kg−1), ce qui est nettement inférieur aux critères de potabilité de l'eau de l'OMS (100 Bq·l−1).[3] La méthode présentée dans le présent document n'est pas applicable à la détermination de la quantité de 99Tc à l'état d'ultra-traces.
Les valeurs de concentration en masse indiquées dans le présent document sont exprimées en unité de masse d'échantillon, et non en unité de volume d'échantillon comme c'est habituellement le cas dans les normes similaires. Cela tient au fait que 99Tc est mesuré dans différents types de matrices tels que l'eau douce ou l'eau de mer, qui présentent des masses volumiques très différentes. Les valeurs de concentration en masse peuvent être facilement converties en unité de volume d'échantillon en mesurant le volume d'échantillon. Cependant, cela accroît l'incertitude applicable au résultat de la concentration en masse.
La méthode décrite dans le présent document est applicable en cas d'urgence, mais pas si 99mTc est présent à des quantités susceptibles de provoquer des interférences.
L'analyse de Tc adsorbé dans la matière en suspension n'est pas couverte par la présente méthode.
Il incombe à l'utilisateur de s'assurer que la méthode d'essai relative aux échantillons d'eau soumis à essai est valide.

Kakovost vode - Tehnecij Tc-99 - 2. del: Preskusna metoda z masno spektrometrijo z induktivno sklopljeno plazmo (ICP-MS) (ISO 22125-2:2019)

Ta standard določa metodo za merjenje tehnecija 99Tc v vseh vrstah vode z masno spektrometrijo z induktivno sklopljeno plazmo (ICP-MS).
Metoda, opisana v tem standardu, s trenutno razpoložljivo masno spektrometrijo ima mejo zaznavnosti približno 0,2–0,5 ng•l-1 (0,1–0,3 Bq•kg-1), ki je precej nižja od meril organizacije WHO za varno porabo pitne vode (100 Bq•l-1). Metoda, predstavljena v tem standardu, ni namenjena določanju količine ultra-sledov tehnecija 99Tc.

General Information

• Status: Published
• Publication Date: 26-Nov-2019
• Withdrawal Date: 30-May-2020
• ICS: 13.060.60 - Examination of physical properties of water
• ICS: 17.240 - Radiation measurements
• Technical Committee: CEN/TC 230 - Water analysis
• Drafting Committee: CEN/TC 230 - Water analysis
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 27-Nov-2019
• Completion Date: 27-Nov-2019
• Ref Project: SIST EN ISO 22125-2:2020 - Water quality - Technetium-99 - Part 2: Test method using inductively coupled plasma mass spectrometry (ICP-MS) (ISO 22125-2:2019)

Overview

EN ISO 22125-2:2019 - Water quality - Technetium-99 - Part 2: Test method using inductively coupled plasma mass spectrometry (ICP‑MS) is a CEN-endorsed ISO method for measuring technetium‑99 (99Tc) in all types of water using ICP‑MS. The standard defines scope, sample preparation, measurement by ICP‑MS, quality assurance and reporting requirements. It covers supply/drinking water, rainwater, surface and groundwater, cooling and industrial waters, and domestic/industrial wastewater (after appropriate sampling, filtration and preparation).

Key SEO phrases: EN ISO 22125-2:2019, Technetium‑99, ICP‑MS, water quality, radionuclide analysis.

Key topics and requirements

• Scope and applicability: Measurement of 99Tc in dissolved phase of diverse water matrices; analysis of Tc adsorbed to suspended matter is excluded.
• Sample handling: Filtration of test samples is required before analysis; proper sampling, preservation and preparation are emphasized.
• Analytical technique: Inductively coupled plasma mass spectrometry (ICP‑MS) is the specified measurement technique.
• Detection capability: Typical detection limits with current ICP‑MS systems are approximately 0.2–0.5 ng·kg−1 (≈ 0.1–0.3 Bq·kg−1). This sensitivity is well below the WHO drinking‑water guidance level (100 Bq·L−1). The method is not intended for ultra‑trace 99Tc determinations.
• Units and conversion: Results are expressed as mass concentration per sample mass (kg). Conversion to volume units (e.g., Bq·L−1) is possible by measuring sample volume but increases uncertainty.
• Interferences and emergency use: The method can be applied in emergency situations but is not suitable if interfering quantities of 99mTc are present.
• Quality assurance: The standard includes instrument verification, contamination control, interference control, method verification, tracer and recovery approaches, detection limit and limit of quantification calculations. Annexes describe specific chemical separation/resin approaches (TEVA, TRU, anion exchange).

Applications

• Routine and regulatory monitoring of 99Tc in drinking water, surface and groundwater, industrial effluents and cooling waters.
• Environmental surveillance around nuclear facilities and waste management sites.
• Emergency response monitoring when assessing radiological contamination of water (subject to interference constraints).
• Laboratory method validation, QA/QC program development and reporting for radionuclide water analysis.

Who should use this standard

• Environmental and public‑health laboratories performing radionuclide analysis.
• Water utilities and regulatory agencies responsible for drinking‑water compliance.
• Nuclear facility laboratories, emergency response teams and accredited testing bodies using ICP‑MS for radioanalytical work.

Related standards

• ISO 22125 series (other parts dealing with technetium and alternative methods) and general ISO guidance on sampling, radioactivity measurements and uncertainty reporting (refer to ISO/TC 147 work items).

This summary helps water testing laboratories and regulators understand the practical scope, technical requirements and typical performance of EN ISO 22125-2:2019 for 99Tc determination by ICP‑MS.

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2020
Kakovost vode - Tehnecij Tc-99 - 2. del: Preskusna metoda z masno
spektrometrijo z induktivno sklopljeno plazmo (ICP-MS) (ISO 22125-2:2019)
Water quality - Technetium-99 - Part 2: Test method using inductively coupled plasma
mass spectrometry (ICP-MS) (ISO 22125-2:2019)
Wasserbeschaffenheit - Technetium 99 - Teil 2: Verfahrens mittels Massenspektronomie
und induktiv gekoppeltem Plasma (ICP-MS) (ISO 22125-2:2019)
Qualité de l'eau - Technétium-99 - Partie 2: Méthode d’essai par spectrométrie de masse
couplée à un plasma induit (ISO 22125-2:2019)
Ta slovenski standard je istoveten z: EN ISO 22125-2:2019
ICS:
13.060.50 Preiskava vode na kemične Examination of water for
snovi chemical substances
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 22125-2
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2019
EUROPÄISCHE NORM
ICS 13.060.60; 17.240
English Version
Water quality - Technetium-99 - Part 2: Test method using
inductively coupled plasma mass spectrometry (ICP-MS)
(ISO 22125-2:2019)
Qualité de l'eau - Technétium-99 - Partie 2: Méthode Wasserbeschaffenheit - Technetium 99 - Teil 2:
d'essai par spectrométrie de masse couplée à un Verfahrens mittels Massenspektronomie und induktiv
plasma induit (ISO 22125-2:2019) gekoppeltem Plasma (ICP-MS) (ISO 22125-2:2019)
This European Standard was approved by CEN on 8 September 2019.

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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22125-2:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 22125-2:2019) has been prepared by Technical Committee ISO/TC 147 "Water
quality" in collaboration with 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 May 2020, and conflicting national standards shall be
withdrawn at the latest by May 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.
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 22125-2:2019 has been approved by CEN as EN ISO 22125-2:2019 without any
modification.
INTERNATIONAL ISO
STANDARD 22125-2
First edition
2019-11
Water quality — Technetium-99 —
Part 2:
Test method using inductively coupled
plasma mass spectrometry (ICP-MS)
Qualité de l'eau — Technétium-99 —
Partie 2: Méthode d’essai par spectrométrie de masse couplée à un
plasma induit (ICP-MS)
Reference number
ISO 22125-2:2019(E)
©
ISO 2019
ISO 22125-2:2019(E)
© ISO 2019
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 2019 – All rights reserved

ISO 22125-2:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 2
4 Principle . 4
5 Sampling, handling and storage . 4
6 Procedure. 4
6.1 Sample preparation for measurement . 4
6.2 Sample measurement . 5
7 Quality assurance and quality control program . 5
7.1 General . 5
7.2 Variables that could influence the measurement . . 5
7.3 Instrument verification. 5
7.4 Contamination . 5
7.5 Interference control . 6
7.6 Method verification . 6
7.7 Demonstration of analyst capability . 6
8 Expression of results . 6
97 98
8.1 Using Re, Tc, or Tc as a recovery tracer . 6
8.1.1 Calculation of mass of tracer and analyte added. 6
8.1.2 Measurement bias . 7
8.1.3 Sample mass concentration . 7
8.1.4 Detection limit . 8
8.1.5 Limit of quantification . 8
95m 97m 99m
8.2 Using Tc, Tc or Tc as a recovery tracer . 8
8.2.1 Calculation of activity of tracer, mass of analyte and mass of internal
standard added . 8
8.2.2 Purification step recovery . 9
8.2.3 Measurement bias . 9
8.2.4 Sample mass concentration . 9
8.2.5 Detection limit . 9
8.2.6 Limit of quantification .10
8.2.7 Conversion of mass concentration to activity concentration .10
8.2.8 Conversion of mass concentration to volume unit .10
8.3 Correction for the presence of Tc in the tracer . .11
9 Test report .11
Annex A (informative) Method 1 — TEVA resin .12
Annex B (informative) Method 2 — TRU resin .15
Annex C (informative) Method 3 — Anion exchange resin .18
Bibliography .21
ISO 22125-2:2019(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 on 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 the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 3,
Radioactivity measurements.
A list of all the parts in the ISO 22125 series can be found on the ISO website.
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 2019 – All rights reserved

ISO 22125-2:2019(E)
Introduction
Radioactivity from several naturally-occurring and anthropogenic sources is present throughout the
environment. Thus, water bodies (such as surface waters, ground waters, sea waters) can contain
radionuclides of natural, human-made, or both origin.
40 3 14
— Natural radionuclides, including K, H, C, and those originating from the thorium and uranium
226 228 234 238 210 210
decay series, in particular Ra, Ra, U, U, Po and Pb can be found in water for natural
reasons (such as desorption from the soil and washoff by rain water) or can be released from
technological processes involving naturally occurring radioactive materials (such as the mining
and processing of mineral sands or phosphate fertilizers production and use).
— Human-made radionuclides such as transuranium elements (americium, plutonium, neptunium,
3 14 90
curium), H, C, Sr, and gamma emitting radionuclides can also be found in natural waters.
Small quantities of these radionuclides are discharged from nuclear fuel cycle facilities into the
environment as a result of authorized routine releases. Some of these radionuclides used for
medical and industrial applications are also released into the environment after use. Anthropogenic
radionuclides are also found in waters as a result of past fallout contaminations resulting from
the explosion in the atmosphere of nuclear devices and accidents such as those that occurred in
Chernobyl and Fukushima.
Radionuclide activity concentration in water bodies can vary according to local geological
characteristics and climatic conditions and can be locally and temporally enhanced by releases from
[1]
nuclear installation during planned, existing, and emergency exposure situations . Drinking water
may thus contain radionuclides at activity concentrations which could present a risk to human health.
The radionuclides present in liquid effluents are usually controlled before being discharged into
[2]
the environment and water bodies. Drinking waters are monitored for their radioactivity as
[3]
recommended by the World Health Organization (WHO) so that proper actions can be taken to ensure
that there is no adverse health effect to the public. Following these international recommendations,
national regulations usually specify radionuclide authorized concentration limits for liquid effluent
discharged to the environment and radionuclide guidance levels for waterbodies and drinking waters
for planned, existing, and emergency exposure situations. Compliance with these limits can be assessed
using measurement results with their associated uncertainties as specified by ISO/IEC Guide 98-3 and
[4]
ISO 5667-20 .
Depending on the exposure situation, there are different limits and guidance levels that would result in
an action to reduce health risk. As an example, during planned or existing situation, the WHO guidelines
−1 99 [3]
for guidance level in drinking water is 100 Bq·l for Tc activity concentration.
NOTE 1 The guidance level is the activity concentration with an intake of 2 l/d of drinking water for one year
that results in an effective dose of 0,1 mSv/a for members of the public. This is an effective dose that represents a
[3]
very low level of risk and which is not expected to give rise to any detectable adverse health effects .
[5]
In the event of a nuclear emergency, the WHO Codex Guideline Levels mentioned that the activity
−1 99
concentration in contaminated food might not be greater than 10 000 Bq·kg for Tc.
NOTE 2 The Codex guidelines levels (GLs) apply to radionuclides contained in foods destined for human
consumption and traded internationally, which have been contaminated following a nuclear or radiological
emergency. These GLs apply to food after reconstitution or as prepared for consumption, i.e. not to dried or
concentrated foods, and are based on an intervention exemption level of 1 mSv in a year for members of the
[5]
public (infant and adult) .
Thus, the test method can be adapted so that the characteristic limits, decision threshold, detection
limit and uncertainties ensure that the radionuclide activity concentrations test results can be verified
to be below the guidance levels required by a national authority for either planned/existing situations
[5][6][7]
or for an emergency situation .
Usually, the test methods can be adjusted to measure the activity concentration of the radionuclide(s)
in either wastewaters before storage or in liquid effluents before being discharged to the environment.
ISO 22125-2:2019(E)
The test results will enable the plant/installation operator to verify that, before their discharge,
wastewaters/liquid effluent radioactive activity concentrations do not exceed authorized limits.
The test method(s) described in this document may be used during planned, existing and emergency
exposure situations as well as for wastewaters and liquid effluents with specific modifications that
could increase the overall uncertainty, detection limit, and threshold.
The test method(s) may be used for water samples after proper sampling, sample handling, and test
sample preparation (see the relevant part of the ISO 5667 series).
This document has been developed to answer the need of test laboratories carrying out these
measurements, that are sometimes required by national authorities, as they may have to obtain a
specific accreditation for radionuclide measurement in drinking water samples.
This document is one of a set of International Standards on test methods dealing with the measurement
of the activity concentration of radionuclides in water samples.
vi © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 22125-2:2019(E)
Water quality — Technetium-99 —
Part 2:
Test method using inductively coupled plasma mass
spectrometry (ICP-MS)
WARNING — Persons using this document should be familiar with normal laboratory practices.
This document 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
determine the applicability of any other restrictions.
IMPORTANT — It is absolutely essential that tests conducted according to this test method be
carried out by suitably trained staff.
1 Scope
This document specifies a method for the measurement of Tc in all types of water by inductively
coupled plasma mass spectrometry (ICP-MS).
The method is applicable to test samples of supply/drinking water, rainwater, surface and ground water,
as well as cooling water, industrial water, domestic, and industrial wastewater after proper sampling
and handling and test sample preparation. A filtration of the test sample is necessary.
The detection limit depends on the sample volume and the instrument used. The method described in
−1
this document, using currently available ICP-MS, has a detection limit of approximately 0,2 ng·kg to
−1 −1 −1
0,5 ng·kg (0,1 Bq·kg to 0,3 Bq·kg ), which is much lower than the WHO criteria for safe consumption
−1 [3]
of drinking water (100 Bq·l ) . The method presented in this document is not intended for the
determination of ultra-trace amount of Tc.
The mass concentration values in this document are expressed by sample mass unit instead of sample
volume unit as it is usually the case in similar standards. The reason is that Tc is measured in various
matrix types such as fresh water or sea water, which have significant differences in density. The mass
concentration values can be easily converted to sample volume unit by measuring the sample volume.
However, it increases the uncertainty on the mass concentration result.
The method described in this document is applicable in the event of an emergency situation, but not if
99m
Tc is present at quantities that could cause interference.
The analysis of Tc adsorbed to suspended matter is not covered by this method.
It is the user’s responsibility to ensure the validity of this test method for the water samples tested.
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/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
me a s ur ement (GUM: 1995)
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM)
ISO 22125-2:2019(E)
ISO 3696, Water for analytical laboratory use — Specification and test methods
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 5667-10, Water quality — Sampling — Part 10: Guidance on sampling of waste waters
ISO 10703, Water quality — Determination of the activity concentration of radionuclides — Method by
high resolution gamma-ray spectrometry
ISO 11929 (all parts), 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 17294-2, Water quality — Application of inductively coupled plasma mass spectrometry (ICP-MS) —
Part 2: Determination of selected elements including uranium isotopes
ISO 20042, Measurement of radioactivity — Gamma emitting radionuclides — Generic test method using
gamma spectrometry
ISO 80000-10, Quantities and units — Part 10: Atomic and nuclear physics
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 80000-10, ISO 11929,
ISO/IEC Guide 98-3 and ISO/IEC Guide 99 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/
3.2 Symbols
For the purposes of this document, the symbols and designations given in ISO 80000-10, ISO 11929,
ISO/IEC Guide 98-3, ISO/IEC Guide 99 and the following apply.
Symbol Term Unit Definition
symbol
α Measurement bias — α is a constant which allows to correct for the signal
intensity bias between the tracer or the internal standard
and the analyte
−1
C Activity concentration Bq·kg Corresponding to the activity concentration ρ measured for
a given radionuclide
−1
C Specific activity Bq∙g Activity corresponding to one gram of the radionuclide
s
−1
DL Detection limit in mass g∙kg DL is the lowest mass concentration that can be considered
concentration statistically different from a blank sample.
−1
DL Detection limit in activity Bq∙kg DL is the lowest activity concentration that can be
C
concentration considered statistically different from a blank sample.
−1
LOQ Limit of quantification in g∙kg LOQ is the lowest mass concentration that can be quantified
mass concentration with statistically certainty
2 © ISO 2019 – All rights reserved

ISO 22125-2:2019(E)
Symbol Term Unit Definition
symbol
−1
LOQ Limit of quantification in Bq∙kg LOQ is the lowest activity concentration that can be
C
activity concentration quantified with statistically certainty
m Sample mass kg Mass of the water sample
m/z Mass on charge ratio — Mass on charge ratio measured by the ICP-MS
m Analyte mass g Mass of analyte added to a spiked solution
A
m Analyte solution mass g Mass of the analyte solution added to a control sample or for
As
measurement calculation
m Internal standard mass g Mass of the internal standard added to the blank and sample
IS
m Internal standard solution g Mass of the internal standard solution added to a blank
ISS
mass sample or a sample
m Tracer mass g Mass of the tracer added to the blank and sample
T
m Reagent blank tracer mass g Mass of tracer added to the reagent blank for the
TB
calculation of N
net
m Tracer solution mass g Mass of the tracer solution added to a blank sample or a
TS
sample
N Counts counts Number of counts directly obtained when performing
the ICP-MS measurement for a sample at a given mass on
charge ratio
N Counts of the blank counts Number of counts directly obtained when performing
the ICP-MS measurement for a blank at a given mass on
charge ratio
Average counts of blank counts Average number of counts directly obtained when
N samples performing the ICP-MS measurement for several blanks at a
given mass on charge ratio
N Net counts counts N-N
net 0
N Net counts of the internal counts At the internal standard mass
netIS
standard
N Net counts of the tracer counts At the tracer mass
netT
N spiked reagent blank count counts spiked reagent blank count rate for N calculation
sp net
99 99
N Tc counts from the tracer counts Tc present in the tracer as impurities
T
N Unspiked reagent blank counts Unspiked reagent blank count rate for N calculation
us net
R Chemical recovery — Recovery of the purification step obtained by gamma
c
measurement
S Standard deviation counts
s Standard deviation counts Standard deviation associated with the measurement
N0
obtained from 10 test portions of a blank sample
U Expanded uncertainty — Product of the standard uncertainty and the coverage factor
k with k = 1, 2,…, U = k · u
μ Standard uncertainty — Uncertainty of a term such as mass, counts, etc.
−1
μ[C] Standard uncertainty of the Bq∙kg Standard uncertainty associated with the activity
activity concentration concentration result
−1
μ[ρ] Standard uncertainty of the g∙kg Standard uncertainty associated with the mass
mass concentration concentration result
−1
ρ Mass concentration g∙kg Analyte mass for a given radionuclide per sample unit mass
−1
ρ Mass concentration of the g∙g Analyte mass for a given radionuclide per sample unit
A
analyte ( Tc) standard volume of the standard solution
solution
−1
ρ Mass concentration of the g∙g Tracer mass for a given radionuclide per sample unit volume
Τ
tracer solution of the tracer solution
ISO 22125-2:2019(E)
4 Principle
Technetium is mainly an anthropogenic element, but trace amounts are found in uranium ores. It has no
99 235 [8]
stable isotope. Tc is a significant fission product of U (approximately 6 % yield ) with a maximum
5 [9]
beta-energy of (294 ± 1) keV and a half-life of 2,1 ± 0,1 × 10 years .
To determine Tc in water, a water sample is collected, filtered, acidified, and oxidized (see Clause 5 on
sampling and storage).
A tracer is added before the chemical separation to take into account the losses during the purification
step. Enough tracer is added to obtain a good statistical precision and be easily distinguished from a
95m 97m 97 98 99m
blank sample. The tracers that can be used are stable Re, Tc, Tc, Tc, Tc, and Tc.
95m 99m 97 98
Tc and Tc are the easiest Tc isotopes to be obtained commercially. Tc and Tc are not currently
95m 97m 99m
commercially available. The isotopes Tc, Tc, and Tc have a short radiological half-life and
cannot be used as an internal standard (IS) (they are not measured by ICP-MS) to correct the variation
of signal by the ICP-MS instrument; thus, an internal standard such as In is added before the
99m 99 [10]
measurement. When using Tc, the standard should contain as little Mo as possible . The activity
95m 99m
of Tc and Tc are measured by gamma spectrometry according to ISO 10703 and ISO 20042.
[8]
Stable Re is often used as a recovery tracer for Tc measurement due to its similar reactivity . It has the
advantages of being easily available, stable, and can be measured by ICP-MS. Tc and Re do not behave
[11][12]
similarly when heated in an acidic solution: Tc is more volatile ; thus, Re cannot be used as a
recovery tracer when the method includes an evaporation step.
The potential interferents for the measurement of Tc by ICP-MS are removed chemically. The two
98 + 99 + 99
main interferents are MoH and Ru . Methods for the purification of Tc are presented in detail in
the Annexes A to C.
99 99
Finally, Tc is measured by ICP-MS and the mass or activity concentration of Tc is calculated and
reported (see 6.2 for more details).
5 Sampling, handling and storage
Sampling, handling and storage of the water shall be done as specified in ISO 5667-1, ISO 5667-3 and
ISO 5667-10 and guidance is given for the different types of water in References [13] to [20]. It is
important that the laboratory receives a sample that is truly representative and has not been damaged
or modified during transportation or storage.
The sample is filtered to remove suspended matter using a 0,45 μm filter. A smaller pore size filter
can also be used, but the filtration might be more tedious and time consuming. Technetium (VII) is
not strongly adsorbed to plastic or glass container, but it could be reduced by the organic matter in
the sample to technetium oxide (TcO ). After filtration, the sample is acidified with nitric acid (HNO )
2 3
−1 -
to 0,01 mol·l HNO . Then, hydrogen peroxide (H O ) is added to maintain Tc as TcO and reduce its
3 2 2 4
−1
adsorption to the container. An addition of H O to bring the sample to a concentration of 0,02 mol·l is
2 2
recommended for the sample.
6 Procedure
6.1 Sample preparation for measurement
Filter, acidify, and oxidize the samples and a blank sample prepared with ultrapure water as specified
in Clause 5. A minimum of 1 blank sample, which contains the tracer, is required for all the method
presented. However, the average of several blanks can be used. Also, measuring blank samples at
regular interval enables to rapidly detect a background issue when measuring the samples (for quality
assurance and quality control program, see Clause 7).
4 © ISO 2019 – All rights reserved

ISO 22125-2:2019(E)
Add the tracer as specified in one of the purification methods described in Annexes A to C. An equivalent
method can be used but shall follow all the criteria enounced in this document.
Purify the samples from potential interferents using one of the methods presented in the Annexes A, B
or C.
95m 97m 99m
For Tc, Tc and Tc tracers only, determine the recovery by gamma spectrometry and add the
internal standard to the sample.
Measure the Tc and tracer or internal standard signal intensity by ICP-MS.
6.2 Sample measurement
The Tc and tracer or internal standard signal intensity are measured by the ICP-MS instrument.
The mass concentrations of Tc and the tracer or internal standard employed are measured. The
instructions provided by the instrument manufacturer to use the ICP-MS and the steps described in
ISO 17294-2 should be followed.
The detection sensitivity, the instrumental detection limit, and the measurement precision should
be established for each analysis performed on the instrument. The interferences for the masses of
interest should be reported in a separate table. The measurement bias should be determined for each
measurement.
A rinsing sequence, which enables the signal intensity for the analyte and tracer or internal standard to
return down to background level, shall be performed after each sample measurement. Memory effects
often occur when measuring Tc and Re by ICP-MS. The sample introduction system may be rinsed using
a solution of HNO (e.g. 2 %) followed by water. The acid and water used are at least of ICP-MS grade.
Then a blank solution should be processed to verify that all remaining Tc and Re have been removed
from the system.
7 Quality assurance and quality control program
7.1 General
Quality control operations shall meet the requirements of ISO/IEC 17025. Measurement methods shall
be performed by suitably skilled staff under a quality assurance program.
7.2 Variables that could influence the measurement
Special care shall be taken in order to limit as much as possible the influence of parameters that may
bias the measurement and lead to a non-representative result. Failure to take sufficient precautions
may require corrective factors to be applied to the measured result.
Influencing variables can affect the following stages of the measurement process: sampling,
transportation and storage, reagents, transfer, and the measurement.
7.3 Instrument verification
Major instrument parameters (detection efficiency, background signal) shall be periodically verified
within a quality assurance program established by the laboratory and in accordance with the
manufacturer’s instructions.
7.4 Contamination
Verify for contamination of the reagents through the periodic performance of reagent blank analysis.
Laboratory procedures shall ensure that laboratory and equipment contamination as well as sample
cross contamination is avoided.
ISO 22125-2:2019(E)
7.5 Interference control
It is the user responsibility to ensure that all potential interferents have been removed. The removal
of potential interferents is limited by the decontamination factor of the method and the instrumental
capabilities.
99 98 + 99 +
The main interferents for Tc measurement by ICP-MS are MoH and Ru . It is of good practice to
monitor these interferents during the measurement step to evaluate their impact on m/z 99. Mo and Ru
can be measured free of interferences at m/z 95 and 101, respectively. If Mo and/or Ru has an influence
on m/z 99, the result obtained should be considered not valid, except if it is corrected. Since Mo and Ru
have several natural isotopes, it is possible to use the natural abundance ratio to correct their influence
on m/z 99. Such a correction affects the measurement precision and the detection limit of the method. It
should only be used if necessary.
7.6 Method verification
A blank solution should be measured at constant interval in a sample sequence. The obtained value shall
be subtracted from the measured sample values. If the blank value exceeds the expected background
value (within measurement limits), follow the recommendations of the instrument manufacturer and
improve the rinsing sequence. In addition, all the results of the measurement obtained before the failing
blank and the last valid blank are considered invalid; thus, ideally a blank solution should be measured
after each sample measurement.
A quality control solution should be measured at constant interval in a sample sequence. It is verified
that the value of the concentration does not deviate from the expected value (within measurement
limits). If the deviation exceeds the established measurement limits (optimum sensitivity, optimum
stability), follow the recommendations of the instrument manufacturer and perform the optimization of
the parameters again. In addition, all the results of the measurement obtained before the failing control
and the last valid control are considered invalid; thus, ideally a control solution should be measured
before each sample.
A periodic verification of the method accuracy should be performed. This may be accomplished by:
— participating in intercomparison exercises;
— analysing reference materials;
— analysing spiked samples.
The repeatability of the method should be verified (for example, by replicate measurements).
7.7 Demonstration of analyst capability
If an analyst has not performed this procedure before, a precision and bias test should be performed
by running a duplicate measurement of a reference or spiked material. Acceptance limits should be
defined by the laboratory.
A similar evaluation should be performed by the analysts who routinely apply this procedure, with a
periodicity defined by the laboratory. Acceptance limits should be defined.
8 Expression of results
97 98
8.1 Using Re, Tc, or Tc as a recovery tracer
8.1.1 Calculation of mass of tracer and analyte added
The sample concentration is determined using a tracer, which corrects for losses during the sample
preparation. The tracer also corrects for instrumental deviations during the measurement. The
tracer solution concentration (ρ ) shall be known, ideally with great precision. Certified solutions are
T
6 © ISO 2019 – All rights reserved

ISO 22125-2:2019(E)
usually employed. A defined quantity of the tracer solution is added to each sample and the mass of
solution added (m ) is recorded. The mass of tracer (m ) added to each sample can be calculated using
Ts T
Formula (1):
mm=ρ (1)
TT Ts
The uncertainty on m can be calculated using Formula (2):
T
2 2
μμmm= ρμ+ m (2)
() () ()
TT rel Trel Ts
To calculate the measurement bias and prepare control or spiked samples, which contains the tracer, a
known amount of Tc shall be added to the sample. For this purpose, a solution of known concentration
99 99
of Tc (ρ ), ideally with great precision, is needed. The mass of Tc solution added is recorded. The
A
mass of Tc added (m ), can be calculated using Formula (3):
A
mm=ρ (3)
AA As
The uncertainty on m can be calculated using Formula (4):
A
2 2
μμmm= ρμ+ m (4)
() () ()
AA rel Arel As
8.1.2 Measurement bias
The measurement bias is a correction factor that corrects for all the measurement deviations between
the tracer and the analyte. It includes correction for the mass bias and the variation of signal intensity
between the tracer and the analyte. When a stable tracer or internal standards is used, it also corrects
for the fact that only one isotope of the element is used for the measurement.
The measurement bias (α) is first determined by measuring with the ICP-MS instrument the number
of counts (cps) obtained for Tc (N ) and for the tracer (N ) using a solution containing a known
net netT
quantity of Tc (m ) and tracer (m ). The measurement bias is determined using Formula (5):
A T
α =⋅mN / mN⋅ (5)
()
()
Anet Tnet
T
And the uncertainty on the measurement bias is determined using Formula (6):
2 2 2 2
μα =αμ mm+μμ+ NN+μ (6)
() () () () ()
relrA el Trel netrel netT
8.1.3 Sample mass concentration
The test sample mass concentration (ρ) in Tc is calculated using Formula (7):
ρα=⋅mN⋅ / mN⋅ (7)
() ()
Tnet netT
The uncertainty on the sample mass concentration is calculated using Formula (8):
2 2 2 2 2
μρ = ρμ mN+ μμ+ Nm++μα μ (8)
() () () () ()
rel Trel netrel netT rel rel
ISO 22125-2:2019(E)
8.1.4 Detection limit
The detection limit (DL) corresponds to 3 times the standard deviation (s ) associated with the
N0
measurement obtained from 10 test portions of a blank sample which has passed through all the steps
of the method. The standard deviation on the measured counts is converted in g per kg of sample using
Formula (9):
DL=⋅α mN⋅+3⋅Sm/ ⋅N (9)
()
)
()TN( 0 netT
8.1.5 Limit of quantification
The limit of quantification (LOQ) for a given mass, can be evaluated as 10 times the standard deviation
(s ) associated with the measurement obtained for 10 test portions of the blank, which corresponds to
N0
10/3 of the DL as expressed in Formula (10):
LOQD=⋅10/3 L (10)
95m 97m 99m
8.2 Using Tc, Tc or Tc as a recovery tracer
8.2.1 Calculation of activity of tracer, mass of analyte and mass of internal standard added
The sample activity is determined using a recovery tracer, which corrects for losses during the sample
preparation. The instrumental deviations during the measurement are corrected using an internal
standard. The activity concentration of the tracer solution (C ) and the internal standard mass
Ts
concentration (ρ ) shall be known,
...