oSIST prEN ISO 22125-2:2026

• Abstract:

  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.

• Status: Not Published
• Public Enquiry End Date: 14-Sep-2026
• ICS: 13.060.50 - Examination of water for chemical substances
• ICS: 13.060.60 - Examination of physical properties of water
• ICS: 17.240 - Radiation measurements
• Technical Committee: KAV - Water quality
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 21-Jul-2026
• Due Date: 08-Dec-2026
• Completion Date: 24-Sep-2026
• Ref Project: prEN ISO 22125-2 - Water quality - Technetium-99 - Part 2: Test method using inductively coupled plasma mass spectrometry (ICP-MS) (ISO/DIS 22125-2:2026)

• Revises: 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)
• Effective Date: 01-Sep-2026

Overview

oSIST prEN ISO 22125-2:2026: Water quality - Technetium-99 - Test method using ICP-MS is a draft international standard developed by CEN and ISO. It outlines a robust analytical procedure for the measurement of technetium-99 (^99Tc) in a range of water matrices using inductively coupled plasma mass spectrometry (ICP-MS). This method is designed to support environmental monitoring, regulatory compliance, and emergency response related to radioactive contamination in water.

The standard applies to supply and drinking water, rainwater, surface water, groundwater, marine water, industrial water, and wastewaters. It emphasizes careful sample filtration, preparation, and the use of quality assurance procedures to achieve reliable results at low detection levels.

Key Topics

• Technetium-99 Detection: Specifies a sensitive ICP-MS-based method to quantify technetium-99, a significant anthropogenic radionuclide found in water due to nuclear activities and medical applications.
• Sample Types: Applicable to various waters, including drinking water, rainwater, surface water, groundwater, cooling water, industrial water, and domestic/industrial wastewater.
• Sample Preparation: Requires filtration to remove suspended particles, followed by acidification and oxidation to maintain ^99Tc stability.
• Low Detection Limits: Achieves detection limits of approximately 0.2–0.5 ng·kg^−1 (0.1–0.3 Bq·kg^−1), well below the World Health Organization guideline of 100 Bq·l^−1 for drinking water safety.
• Interference Control: Addresses common spectral interferences in ICP-MS (e.g., isobaric and polyatomic), ensuring results are valid only when these are managed.
• Matrix Considerations: All result concentrations are expressed per unit mass, not volume, to account for density differences in various waters, such as seawater versus freshwater.
• Quality Assurance: Mandates procedures for instrument calibration, use of certified standards, quality control samples, and staff competence as per recognized laboratory practices.

Applications

• Environmental Monitoring: Enables routine assessment of technetium-99 levels in natural water bodies near nuclear sites or in regions affected by radioactive fallout.
• Drinking Water Safety: Supports compliance with national and international regulations on radioactivity in public water supplies, protecting public health.
• Industrial and Wastewater Analysis: Applies to monitoring discharges from nuclear fuel reprocessing, medical facilities, or industries handling radioactive substances.
• Emergency Response: Provides a method for rapid and accurate ^99Tc determination following accidental releases or contamination incidents, provided interfering short-lived isotopes are not present in high quantities.
• Regulatory Reporting: Supplies reliable data necessary for regulatory submissions, environmental impact assessments, and compliance verification.

Related Standards

• ISO 17294-1:2024: Application of inductively coupled plasma mass spectrometry (ICP-MS) - General requirements.
• ISO 5667 Series: Guidance on sampling, handling, and storage of water samples.
• ISO/IEC 17025: General requirements for the competence of testing and calibration laboratories.
• ISO 10703 / ISO 20042: Gamma-ray spectrometry methods relevant for comparison or supporting analysis.
• ISO 22125-1: Related part covering laboratory test methods for technetium-99 by different analytical techniques.

Practical Value

Implementing oSIST prEN ISO 22125-2:2026 enables laboratories and water authorities to:

• Detect technetium-99 at levels relevant for public and environmental safety.
• Meet increasing demands for high-sensitivity radionuclide monitoring in water.
• Respond swiftly and reliably in emergencies involving radiological contamination.
• Fulfill regulatory and international obligations regarding radioactive water pollution.
• Support transparent, science-based water quality management.

By following this standard, users ensure the consistency, accuracy, and comparability of technetium-99 ICP-MS determination across various water types and monitoring contexts.

SLOVENSKI STANDARD
01-september-2026
Kakovost vode - Tehnecij Tc-99 - 2. del: Preskusna metoda z masno
spektrometrijo z induktivno sklopljeno plazmo (ICP-MS) (ISO/DIS 22125-2:2026)
Water quality - Technetium-99 - Part 2: Test method using inductively coupled plasma
mass spectrometry (ICP-MS) (ISO/DIS 22125-2:2026)
Wasserbeschaffenheit - Technetium 99 - Teil 2: Verfahren mittels Massenspektrometrie
und induktiv gekoppeltem Plasma (ISO/DIS 22125-2:2026)
Qualité de l'eau - Technétium-99 - Partie 2: Méthode d’essai par spectrométrie de masse
avec plasma à couplage inductif (ICP-MS) (ISO/DIS 22125-2:2026)
Ta slovenski standard je istoveten z: prEN ISO 22125-2
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.

DRAFT
International
Standard
ISO/DIS 22125-2
ISO/TC 147/SC 3
Water quality — Technetium-99 —
Secretariat: AFNOR
Part 2:
Voting begins on:
Test method using inductively 2026-07-02
coupled plasma mass spectrometry
Voting terminates on:
2026-09-24
(ICP-MS)
Qualité de l'eau — Technétium-99 —
Partie 2: Méthode d’essai par spectrométrie de masse couplée à
un plasma induit (ICP-MS)
ICS: 13.060.60; 17.240
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 22125-2:2026(en)
DRAFT
ISO/DIS 22125-2:2026(en)
International
Standard
ISO/DIS 22125-2
ISO/TC 147/SC 3
Water quality — Technetium-99 —
Secretariat: AFNOR
Part 2:
Voting begins on:
Test method using inductively
coupled plasma mass spectrometry
Voting terminates on:
(ICP-MS)
Qualité de l'eau — Technétium-99 —
Partie 2: Méthode d’essai par spectrométrie de masse couplée à
un plasma induit (ICP-MS)
ICS: 13.060.60; 17.240
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2026
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 22125-2:2026(en)
ii
ISO/DIS 22125-2:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
4 Symbols . 2
5 Principle . 3
6 Sampling, handling and storage . 5
7 Procedure . 5
7.1 General .5
7.2 Chemical reagents .5
7.3 Apparatus .6
8 Separation . 6
9 Quality assurance and quality control program . 6
9.1 General .6
9.2 Variables that could influence the measurement .6
9.3 Instrument verification .6
9.4 Method verification .7
10 Expression of results . 8
10.1 Data analysis .8
10.2 Background .8
10.3 Internal standard .8
97 98
10.4 Expression of results using Re, Tc, or Tc as a recovery tracer .9
10.4.1 Calculation of mass of tracer and mass of analyte added .9
10.4.2 Measurement bias .9
10.4.3 Sample mass concentration .9
95m 99m
10.5 Expression of results using Tc or Tc as a recovery tracer .10
10.5.1 Calculation of mass of tracer and mass of analyte added .10
10.5.2 Chemical recovery .10
10.5.3 Measurement bias .10
10.5.4 Sample mass concentration .11
10.6 Limit of detection .11
10.7 Limit of quantification .11
10.8 Correction for Tc contamination in the tracer .11
10.9 Conversion of mass concentration to activity concentration . 12
10.10 Conversion from volume to mass unit . 12
11 Test report .12
Annex A (informative) Method 1 — Chromatographic extraction chromatography resin
functionalized with Trialkyl methylammonium resin . 14
Annex B (informative) Method 2 — Octylphenyl-N,N-di-isobutyl carbamoylphosphine oxide
(CMPO) dissolved in tri-n-butyl phosphate (TBP) extraction chromatography resin . 17
Annex C (informative) Method 3 — Anion exchange resin .20
Bibliography .23

iii
ISO/DIS 22125-2:2026(en)
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 (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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.
This second edition cancels and replaces the first edition (ISO 22125-2:2019), which has been technically
revised.
The main changes are as follows:
— The format of the standard has been modified to align with the most recent ones;
— The most recent version of the introduction, sampling, quality assurance and quality control, and the
test report sections have been added;
— The formulae and their symbols have been reviewed.
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/DIS 22125-2:2026(en)
Introduction
Radionuclides are present throughout the environment; thus, water bodies (e.g. surface waters, ground
waters, sea waters) contain radionuclides, which can be of either natural or anthropogenic origin.
3 14 40
— Naturally-occurring radionuclides, including H, C, K and those originating from the thorium and
210 210 222 226 228 227 232 231 234 238
uranium decay series, in particular Pb, Po, Rn, Ra, Ra, Ac, Th, Pa, U and U,
can be found in water bodies due to either natural processes (e.g. desorption from the soil and runoff by
rain water) or released from technological processes involving naturally occurring radioactive materials
(e.g. mining, mineral processing, oil, gas and coal production, water treatment, and the production and
use of phosphate fertilisers).
55 59 63 90 99
— Anthropogenic radionuclides such as Fe, Ni, Ni, Sr, Tc, transuranic elements (e.g. Np, Pu, Am,
60 137
Cm), and some gamma emitting radionuclides, such as Co and Cs, can also be found in natural
waters. Small quantities of anthropogenic radionuclides can be discharged from nuclear facilities to the
environment as a result of authorized routine releases. The radionuclides present in liquid effluents
[1]
are usually controlled before being discharged to the environment and water bodies. Anthropogenic
radionuclides used for medical and industrial applications can be released to the environment after use.
Anthropogenic radionuclides are also found in waters due to contamination from fallout resulting from
above-ground nuclear detonations and accidents such as those that have occurred at the Chornobyl and
Fukushima nuclear facilities.
Radionuclide activity concentrations in water bodies can vary according to local geological characteristics
and climatic conditions and can be locally and temporally enhanced by releases from nuclear facilities
[2][3]
during planned, existing, and emergency exposure situations. Some drinking water sources can thus
contain radionuclides at activity concentrations that can present a human health risk. The World Health
[4]
Organization (WHO) recommends to routinely monitor radioactivity in drinking waters and to take
proper actions when needed to minimize the health risk.
National regulations usually specify the activity concentration limits that are authorized in drinking waters,
water bodies, and liquid effluents to be discharged to the environment. These limits can vary for planned,
existing, and emergency exposure situations. As an example, during either a planned or existing situation,
99 −1[4]
the WHO guidance level for Tc in drinking water is 100 Bq·l , see NOTES 1 and 2. Compliance with
these limits can be assessed using measurement results with their associated uncertainties, as specified by
[5] [6]
ISO/IEC Guide 98-3:2008 and ISO 5667-20:2008 .
[4]
NOTE 1 If the value is not specified in Annex 6 of Reference , the value has been calculated using the formula
[4] [7] [8]
provided in Reference and the dose coefficient data from References and .
[4]
NOTE 2 The guidance level calculated in Reference is the activity concentration that results in an effective dose
−1 −1
of 0,1 mSv·a to members of the public for an intake of 2 l·d of drinking water for one year. This is an effective
dose that represents a very low level of risk to human health and which is not expected to give rise to any detectable
[4]
adverse health effects .
This document contains method(s) to support laboratories, which need to determine Tc in water samples.
The method described in this document can be used for various types of waters (see Clause 1). For ICP-MS
methods, minor modifications to, for example, the sample pre-concentration volume and the interference
separation can be made if needed to ensure that limit of detection, limit of quantification and uncertainties
are below the required limits. This can be done for several reasons such as emergency situations, lower
national guidance limits and operational requirements.

v
DRAFT International Standard ISO/DIS 22125-2:2026(en)
Water quality — Technetium-99 —
Part 2:
Test method using inductively coupled plasma mass
spectrometry (ICP-MS)
1 Scope
Warning — Persons using this document should be familiar with normal laboratory practice. 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.
Warning — It is absolutely essential that tests conducted in accordance with this document be
carried out by suitably qualified staff.
This document specifies methods to determine Tc by inductively coupled plasma mass spectrometry (ICP-
MS) in supply water, drinking water, rainwater, surface and ground water, marine water, as well as cooling
water, industrial water, domestic, and industrial wastewater after proper sampling, handling, and test
sample preparation.
The detection limit depends on the sample volume, the instrument used, the background count rate, the
detection efficiency, the counting time, and the chemical yield. The detection limit of the methods described
−1 −1
in this document, using currently available ICP-MS instrumentation, is approximately 0,2 ng·l to 0,5 ng·l
−1 −1
(0,1 Bq·l to 0,3 Bq·l ), which is much lower than the WHO criteria for safe consumption of drinking water
−1 [4]
(100 Bq·l ) . The methods presented in this document are not intended for the determination of ultra-
trace amount of Tc.
The methods described in this document are applicable in the event of an emergency situation, but not if
99m
Tc is present at quantities that could cause interference.
Filtration of the test sample is necessary for the methods described in this document if suspended solids are
present. The analysis of Tc adsorbed to suspended matter is not covered by this method. The analysis of
the insoluble fraction requires a mineralization step that is not covered by this document. In this case, the
measurement is made on the different phases obtained.
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 17294-1:2024, Water quality — Application of inductively coupled plasma mass spectrometry (ICP-MS) —
Part 1: General requirements
3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in ISO 80000-10, ISO 11929 (all parts),
ISO/IEC Guide 98-3, ISO/IEC Guide 99 and the following apply.

ISO/DIS 22125-2:2026(en)
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/
3.1
measurement bias
constant which allows to correct for the signal intensity bias between the tracer or the internal standard
and the analyte
4 Symbols
For the purposes of this document, the symbols and designations given in ISO 80000-10, ISO 11929 (all parts),
ISO/IEC Guide 98-3 and ISO/IEC Guide 99 and the following apply.
α Measurement bias —
-1
c Reagent concentration mol·l
−1
C Activity concentration Bq·l
−1
C Specific activity corresponding to one gram of the radionuclide Bq∙g
s
C Activity of the tracer Bq
T
−1
C Mass activity of the tracer added to a sample Bq∙g
TS
k The coverage factor —
−1
L Limit of detection in mass concentration, the lowest mass concentration that can be g∙l
D
considered statistically different from a blank sample.
−1
L Limit of detection in activity concentration, the lowest activity concentration that can Bq∙l
DC
be considered statistically different from a blank sample.
−1
L Limit of quantification in mass concentration, the lowest mass concentration that can g∙l
Q
be quantified with statistical certainty
−1
L Limit of quantification in activity concentration, the lowest activity concentration Bq∙l
QC
that can be quantified with statistical certainty
m Mass of the water sample kg
m/z Mass-to-charge ratio measured by the ICP-MS —
m Mass of analyte added to a spiked solution g
A
m Mass of analyte solution added to a control sample or for measurement calculation g
AS
m Mass of the calibration standard tracer added to a sample g
C
m Mass of the calibration standard solution added to a sample g
Cs
m Mass of the internal standard added to a blank and a sample g
IS
m Mass of the internal standard solution added to a blank or a sample g
ISS
m Mass of the tracer added to a blank and a sample g
T
m Mass of tracer added to a reagent blank g
TB
ISO/DIS 22125-2:2026(en)
m Mass of the tracer solution added to a blank or a sample g
TS
-1
N Counts per second measured when performing ICP-MS measurement for a sample at a s
given mass-to-charge ratio
-1
N Counts per second measured when performing ICP-MS measurement of a blank sam- s
ple at a given mass-to-charge ratio
-1
Average number of counts per second for several blank samples measured by ICP-MS s
at a given mass-to-charge ratio
-1
N Net number of counts per second, N-N s
net 0
-1
N Net number of counts per second at the internal standard mass-to-charge ratio s
netIS
-1
N Net number of counts per second in samples where a tracer has been added to assess s
netT
chemical recovery
-1
N Counts per second in the spiked reagent blank s
sp
-1
N Counts per second at analyte mass-to-charge ratio present as impurities s
T
-1
N Counts per second in the unspiked reagent blank sample s
us
R Chemical recovery following purification —
c
-1
S Standard deviation s
-1
S Standard deviation obtained by measuring 10 test portions of the blank sample s
N0
U Expanded uncertainty and the coverage factor k with k = 1, 2,…, U = k · u —
u Standard uncertainty of a term such as mass, counts, etc. —
−1
u(C) Standard uncertainty associated of the activity concentration Bq∙l
−1
u(ρ) Standard uncertainty of the mass fraction g∙kg
Square of the relative standard uncertainty of the term in the braket such as mass, —
counts, etc.
V Sample volume l
−1
ρ Mass fraction of the analyte g∙kg
−1
ρ Mass concentration of the analyte in volume unit g∙l
V
−1
ρ Mass concentration of the analyte in the standard solution g∙l
A
−1
ρ Mass concentration of the internal standard solution g∙l
IS
−1
ρ Mass concentration of the tracer solution g∙l
Τ
5 Principle
The principle of measurement of analytes using ICP-MS is described in ISO 17294-1:2024 and ISO 17294-2.
Technetium-99 is mainly an anthropogenic element, but trace amounts are found in uranium ores. It is a
235 [9]
significant fission product of U (approximately 6 % yield ).
The results can be converted in activity concentrations using specific activity as a conversion factor given in
Table 1.
ISO/DIS 22125-2:2026(en)
The typical measurement time is several minutes per sample, including sample uptake, counting time and
washout before the next sample.
99 [10]
Table 1 — Half-life and specific activity of Tc
Isotope Half-life Specific activity years
−1
a Bq·g
99 5 8
Tc 2,115 (1) ∙ 10 6,32 (3)∙ 10
An example of the limit of detection that can be obtained with ICP-MS is given in Table 2.
Table 2 — Examples of limit of detection
Isotope Limit of detection Limit of detection
−1 −1
ng·l Bq·l
Tc 0,2 0,1
Radionuclide measurement by ICP-MS is affected by several interferences which are outlined in Table 3.
Table 3 — Interferences affecting ICP-MS measurement
Name of interference Description Tc interference
99 +
Isobaric Stable or radioactive isotopes with a similar mass to the analyte Ru
98 +
Polyatomic Stable or radioactive isotopes combining in plasma to form MoH
a polyatomic ion with a similar mass to the analyte
98 + 100 +
Tailing Stable or radioactive isotopes of one or two mass units on either side Mo , Mo
of the analyte with a relatively high abundance (>10 ) relative to the
analyte
It is important to ensure that all potential interferences have been minimized prior to measurement in order
to remove interferences and pre-concentrate Tc prior to measurement.
It is important to know the decontamination factor achievable by chemical and physical separation. This
can initially be assessed by running stable element standards at increasing concentrations to monitor the
impact at m/z = 99.
An aliquot of a water sample can be directly measured by ICP-MS to determine the stable element
composition. High matrix samples, such as seawater, can need to be diluted to a greater extent before being
measured, depending on the sample introduction system of the instrument used; some designs offer online
aerosol dilution capability that can run high matrix samples without prior dilution.
If any interference has an impact on the Tc result that cannot be corrected for, then the result cannot be
considered to be valid.
Chemical and physical separation is required to remove interferences and pre-concentrate Tc prior
to measurement. As described in ISO 17294-1:2024 and ISO 17294-2, a tracer is needed to evaluate the
separation recovery. The tracer can be mixed with an aliquot of sample, followed by chemical and physical
95m 97m 97 98 99m
isolation of the analyte. Stable Re, Tc, Tc, Tc, Tc, and Tc are suitable tracers.
99m
Technetium-95m and Tc are the easiest Tc isotopes to be obtained commercially. Technetium-97 and
98 95m 97m 99m
Tc are not currently 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 [11]
measurement. When using Tc, the standard should contain as little Mo as possible . The activity of
95m 99m
Tc and Tc are measured by gamma spectrometry according to ISO 10703 and ISO 20042.
[9]
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. Technetium and Re do not
[12][13]
behave similarly when heated in an acidic solution: Tc is more volatile . However, the difference in

ISO/DIS 22125-2:2026(en)
volatility can be negligable in some acidic conditions, which have not being fully defined in the literature.
Evaporation in a HNO solution is believed to minimize HTcO volatilization compared to HCl. If Re is used as
3 4
a recovery tracer when the method includes a vaporization step, the laboratory shall ensure that there is no
discrepensy in chemical recovery between Re and Tc.
To quantify any potential interference coming from the reagents, a blank sample is prepared in the same
way as the test samples. This blank sample is prepared using ultrapure water.
6 Sampling, handling and storage
Sampling, handling and storage of the water samples shall be done as specified in ISO 5667-1, ISO 5667-3
[14]
and ISO 5667-10 and guidance is given for the different types of water samples in References ISO 5667-14
[15]
and ISO 5667-4 . It is important that the laboratory receives a sample that is truly representative and has
neither been damaged nor modified during either 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 could be slower. Technetium (VII) is not strongly adsorbed to plastic or glass
container, but it could be reduced by the organic and inorganic matter in the sample to technetium oxide
−1
(TcO ). After filtration, the sample is acidified with ICP-MS grade nitric acid (HNO ) to 0,01 mol·l HNO .
2 3 3
-
Then, hydrogen peroxide (H O ) is added as an oxidizer to maintain Tc as TcO , preventing its reduction to
2 2 4
TcO , and to limit Tc adsorption to the container. An addition of H O to bring the sample to a concentration
2 2 2
−1
of 0,02 mol·l is recommended for the sample.
Minimising all contamination or losses is of primary concern. Impurities in the reagents or dust on the
laboratory equipment, which is in contact with the samples can be potential sources of stable element
contamination that increases the background at m/z = 99. The sample containers can lead to positive or
negative bias in the determination of trace elements by superficial desorption or adsorption.
7 Procedure
7.1 General
The chemical reagents and equipment used for chemical treatment and preparation of the samples are
described in Annex A, Annex B, and Annex C.
Use only reagents of recognized analytical grade.
7.2 Chemical reagents
7.2.1 Ultrapure water, with a resistivity of 18,2 MΩ∙cm at 25 °C and total organic carbon of less than 1
−1
μg∙l . Unless otherwise stated, water refers to ultrapure water.
−1
7.2.2 Instrument blank, for example 0,3 mol·l ICP-MS grade nitric acid, is used to determine the
background count rate of the instrument at selected mass-to-charge ratios.
7.2.3 Technetium-99 solution, which can be used to prepare calibration standards to calculate the
concentration in the sample.
7.2.4 Internal standard solution, prepared with a stable element. For example, In at m/z = 115 has been
found to be suitable for this purpose.
7.2.5 Tracer solution, to determine the chemical recovery. This solution is prepared by dilution of a
standard that is traceable to national and international standards.
7.2.6 Argon gas, for plasma generation in ICP-MS. The user should consult the instrument's manufacturer
on the minimum gas purity required.

ISO/DIS 22125-2:2026(en)
7.3 Apparatus
Usual laboratory apparatus and in particular the following:
7.3.1 Argon supply, equipped with pressure control and suitable extract and gas regulation system.
7.3.2 ICP-MS and associated software, quadrupole (with or without collision or reaction cell capability),
tandem, sector field or multi-collector. Operation at constant temperature is recommended. Follow the
manufacturers instruction for laboratory setup and instrument operation.
7.3.3 Autosampler, if available, and compatible tubing for running multiple samples automatically.
7.3.4 Pipette, suitable for the accurate transfer of calibration standard, tracer and internal standard
solution with a total precision within ±1 %.
7.3.5 Balance, for example, capable of achieving ±0,1 mg precision.
8 Separation
It is the user’s responsibility to ensure that all potential interferences have been removed. The removal
of potential interferences is limited by the decontamination factor of the method and the instrumental
capabilities. Separation methods are outlined in Annex A, Annex B, and Annex C.
9 Quality assurance and quality control program
9.1 General
Measurement methods shall be performed by suitably skilled staff under a quality assurance program, such
as the one that is described in ISO/IEC 17025.
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 within
limits specified by the laboratory.
A similar evaluation procedure should be performed by the analyst who routinely applies this procedure,
with a periodicity defined by the laboratory. Acceptance limits should be within limits specified by the
laboratory.
9.2 Variables that could influence the measurement
Special care shall be taken in order to limit the influence of parameters that can bias the measurement and
lead to a non-representative result. Failure to take sufficient precautions during the different steps of the
measurement process such as sampling, transportation and storage, reagents used, sample transfer can
require corrective factors to be applied to the measured results.
9.3 Instrument verification
Follow the instructions provided by the instrument manufacturer and the steps described in
ISO 17294-1:2024, Clauses 7 and 9 and ISO 17294-2, Clauses 8 to 11.
The instrument sensitivity, detection limit, measurement precision and measurement bias should be
determined for every analysis performed on the instrument.
Before any sample measurement, measure a quality control solution. Ensure that the measured value of
the concentration does not deviate from the expected value (within measurement limits). If the deviation

ISO/DIS 22125-2:2026(en)
exceeds the established laboratory measurement limits (e.g. sensitivity, stability and uncertainty), follow
the recommendations of the instrument manufacturer and perform the optimization of parameters again.
The instrument sensitivity can be determined from Tc calibration standards run by ICP-MS prior to
samples. The concentration of calibration standard solutions should be known with high precision, using a
certified standard.
If a dual-mode detector or similar is used, then detector cross calibration can be required depending on the
activity range of calibration standards measured.
A known amount of standard, m , at a known concentration, ρ , shall be added for each standard, with the
CS C
mass of calibration standard, m , calculated using Formula (1):
C
(1)
The uncertainty on m can be calculated using Formula (2):
C
(2)
A calibration plot can be produced using either the ICP-MS instrument software or a spreadsheet. The
calibration standard concentration can be plotted against the counts per second. A linear calibration line
gives the instrument sensitivity based on Formula (3):
(3)
where
D is the gradient of the calibration line;
y is the counts per second for the analyte in the sample;
x is the analyte mass concentration;
E is the intercept for the y-axis when x = 0.
A linear calibration line gives values for D and E. If a calibration curve is used to determine the mass
concentration of the measurand, the sample matrix effects on the instrument sensitivity is not always
accounted for. The determination of the mass concentration using a recovery tracer is a more robust
approach.
Equipment quality control solutions shall also be measured at regular intervals during the procedure to
verify that the measurement equipment is performing within agreed limits. 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.
An internal standard shall be prepared to monitor and correct for any change in instrument response during
a run, using an element at a similar mass and ionisation energy to Tc that is not present in the sample being
measured, for example, In.
9.4 Method verification
The method should be validated periodically through replicate measurements of appropriate samples such
as spiked samples, reference materials or participation in inter-comparison exercises.
The repeatability of the method should be verified (e.g. by replicate measurements).
99 98 + 99 +
It is of good practice to monitor for the main potential interferences of Tc, such as MoH and Ru , 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.

ISO/DIS 22125-2:2026(en)
10 Expression of results
10.1 Data analysis
The output from the instrument is typically in counts per second. Gross count rates for samples are corrected
for background and change in instrument response using the internal standard. A correction for chemical
recovery is also required.
If dilutions are carried out, apply the appropriate factor to the values of the sample.
10.2 Background
The blank solution is measured as a sample. The obtained value shall be subtracted from the measured
sample values. A blank solution shall be measured at regular intervals to verify that all remaining Tc is
removed from the system by the count rate returning to the background level.
A rinsing sequence, which enables the signal intensity 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.
Depending on the interfering element concentration, more than one rinsing solution of different
concentrations can be required to return the count rate to the background level.
Depending on the instrument software used, it is possible to set a threshold count rate that shall be reached
during the rinsing sequence before moving on to the next sample.
The ICP-MS instrument software can have built-in background correction capability. The user shall take
care that only one background correction is applied.
10.3 Internal standard
An internal standard shall be added to samples before measurement, including a blank sample. The signal
for the internal standard monitors for changes in instrument performance during a run. This can be due
to small variations in, for example, plasma gas flow rate, or, for higher matrix samples such as seawater,
internal components such as interface cones becoming partially blocked during a run, reducing sample
transmission.
A known amount of internal standard, m , shall be added to the sample. For this purpose, a solution of
IS
known concentration of internal standard, ρ , ideally with great precision, is needed. The mass of internal
IS
standard solution, m , added is recorded. The mass of internal standard added, m , can be calculated using
ISS IS
Formula (4):
(4)
The uncertainty on m can be calculated using Formula (5):
IS
(5)
Some ICP-MS instruments are equipped with online internal standard lines in the sample introduction that
can measure a separate solution containing the internal standard.
The net count rate for the internal standard in each sample should be corrected based on the net count rate
in the first background sample, and this correction factor applied to each sample.
The ICP-MS instrument software can have built-in internal standard correction capability. The user shall
take care that only one internal standard correction is applied.

ISO/DIS 22125-2:2026(en)
97 98
10.4 Expression of results using Re, Tc, or Tc as a recovery tracer
10.4.1 Calculation of mass of tracer and mass of analyte added
The sample activity is determined using a tracer, which corrects for losses during the sample preparation.
The tracer solution concentration, ρ , shall be known, ideally with high precision. Certified standards are
T
usually employed. A defined quantity of the tracer solution is added to each sample and the mass of solution
added, m , is recorded.
TS
The mass of tracer, m , added to each sample can be calculated using Formula (6):
T
(6)
The uncertainty on m can be calculated using Formula (7):
T
(7)
To calculate the measurement bias, control or spiked samples are prepared containing a known concentration
99 99 99
of Tc. A solution of Tc with a concentration known to a
...