kSIST FprEN ISO 16965:2025

SLOVENSKI STANDARD
oSIST prEN ISO 16965:2024
01-september-2024
Trdni matriksi v okolju - Določanje elementov z masno spektrometrijo z induktivno
sklopljeno plazmo (ICP-MS) (ISO/DIS 16965:2024)
Environmental solid matrices - Determination of elements using inductively coupled
plasma mass spectrometry (ICP-MS) (ISO/DIS 16965:2024)
Feststoffe in der Umwelt - Bestimmung von Elementen mittels Massenspektrometrie mit
induktiv gekoppeltem Plasma (ICP-MS) (ISO/DIS 16965:2024)
Matrices solides environnementales - Détermination des éléments par spectrométrie de
masse avec plasma induit par haute fréquence (ICP-MS) (ISO/DIS 16965:2024)
Ta slovenski standard je istoveten z: prEN ISO 16965
ICS:
13.030.20 Tekoči odpadki. Blato Liquid wastes. Sludge
13.080.10 Kemijske značilnosti tal Chemical characteristics of
soils
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
oSIST prEN ISO 16965:2024 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN ISO 16965:2024
oSIST prEN ISO 16965:2024
DRAFT
International
Standard
ISO/DIS 16965
ISO/TC 190/SC 3
Environmental solid matrices —
Secretariat: DIN
Determination of elements using
Voting begins on:
inductively coupled plasma mass
2024-07-09
spectrometry (ICP-MS)
Voting terminates on:
ICS: 13.030.01; 13.080.10
2024-10-01
THIS DOCUMENT IS A DRAFT CIRCULATED
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Reference number
ISO/DIS 16965:2024(en)
oSIST prEN ISO 16965:2024
DRAFT
ISO/DIS 16965:2024(en)
International
Standard
ISO/DIS 16965
ISO/TC 190/SC 3
Environmental solid matrices —
Secretariat: DIN
Determination of elements using
Voting begins on:
inductively coupled plasma mass
spectrometry (ICP-MS)
Voting terminates on:
ICS: 13.030.01; 13.080.10
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 2024
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
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Published in Switzerland Reference number
ISO/DIS 16965:2024(en)
ii
oSIST prEN ISO 16965:2024
ISO/DIS 16965:2024(en)
Contents Page
Foreword .iv
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Principle . 2
4 Interferences . 2
4.1 General .2
4.2 Spectral interferences .2
4.2.1 Isobaric elemental interferences .2
4.2.2 Isobaric molecular and doubly-charged ion interferences .2
4.2.3 Non-spectral interferences .3
5 Reagents . 3
6 Apparatus . 6
7 Procedure . 7
7.1 Test sample solution .7
7.2 Test solution .7
7.3 Instrument set-up .7
7.4 Calibration .7
7.4.1 Linear calibration function .7
7.4.2 Standard addition calibration .8
7.4.3 Determination of correction factors .8
7.4.4 Variable isotope ratio .8
7.5 Sample measurement .8
8 Calculation . 9
9 Expression of results . 9
10 Performance characteristics . 9
10.1 Blank .9
10.2 Calibration check .10
10.3 Internal standard response .10
10.4 Interference .10
10.5 Recovery .10
10.6 Performance data .10
11 Test report . 10
Annex A (informative) Repeatability and reproducibility data .12
Annex B (informative) Selected isotopes and spectral interferences for quadrupole ICP-MS
instruments .18
Bibliography . 19

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oSIST prEN ISO 16965:2024
ISO/DIS 16965:2024(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 patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical
and physical characterization.
This second edition cancels and replaces the first edition (ISO/TS 16965:2013), which has been technically
revised.
The main changes compared to the previous edition are as follows :
— The contents of ISO/TS 16965 and EN 16171 have been merged;
— The scope has been widened to include treated biowaste, waste, sludge and sediment;
— The document has been developed parallel with CEN according to the Vienna Agreement;
— validation data has been added:
— repeatability and reproducibility data have been added from a European interlaboratory comparison
organized by the German Federal Institute for Materials Research and Testing BAM in 2013 (see Annex A).
— repeatability and reproducibility data have been reported as a result of the European interlaboratory
comparison organized by VITO NV in Mol (Belgium) and Synlab Analytics & Services B.V. in Rotterdam
(The Netherlands) for the validation of EN 13656, Digestion with a hydrochloric (HCl), nitric (HNO ) and
tetrafluoroboric (HBF ) or hydrofluoric (HF) acid mixture for subsequent determination of elements. The
validation was performed on the following types of matrices: city waste incineration ash (BCR176/
BCR176R), ink waste sludge (organic matrix), electronic industry sludge (“metallic” matrix), sediment,
coal fly ash, steel slag, copper slag, city waste incineration fly ash ("oxidised" matrix), city waste
incineration bottom ash ("silicate" matrix), sewage sludge (BCR 146R)
— repeatability and reproducibility data have been reported as a result of the European interlaboratory
comparison organized by VITO NV in Mol (Belgium) and Synlab Analytics & Services B.V. in Rotterdam
(The Netherlands) for the validation of EN ISO 54321, Soil, treated biowaste, sludge and waste — Digestion
of aqua regia soluble fraction of elements. The validation was performed on the following types of
matrices: Municipal sludge, Industrial sludge, Sludge from electronic industry, Ink waste sludge, Sewage
sludge, Biowaste, Compost, Composted sludge, Agricultural soil, Sludge amended soil, Waste City waste
incineration fly ash ("oxidised" matrix), City waste incineration bottom ash ("silicate" matrix), Ink waste

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ISO/DIS 16965:2024(en)
sludge (organic matrix), Electronic industry sludge ("metallic" matrix), BCR 146R (sewage sludge), BCR
176 (city waste incineration ash)
— a reference is made to repeatability and reproducibility data obtained from a European interlaboratory
comparison organized by CEN TC 351 for the validation of EN 17200, Construction products: Assessment
of release of dangerous substances — Analysis of inorganic substances in digests and eluates — Analysis by
Inductively Coupled Plasma - Mass Spectrometry (ICP-MS).
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.

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ISO/DIS 16965:2024(en)
Introduction
This document is applicable and validated for several types of matrices as indicated in Table 1 (see Annex A
for the results of validation of sludge, biowaste and soil).
Table 1 — Matrices for which this document is applicable and validated
Matrix Materials used for validation
Sludge Municipal sludge
Industrial sludge
Sludge from electronic industry
Ink waste sludge
Sewage sludge
Biowaste Compost
Composted sludge
Soil Agricultural soil
Sludge amended soils
Waste City waste incineration fly ash ("oxidised" matrix)
City waste incineration bottom ash ("silicate" matrix)
Ink waste sludge (organic matrix)
Electronic industry sludge ("metallic" matrix)
BCR 146R (sewage sludge)
BCR 176 (city waste incineration ash)
Sediments ISE 859 (Sediment from de Bilt / Netherlands)

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DRAFT International Standard ISO/DIS 16965:2024(en)
Environmental solid matrices — Determination of elements
using inductively coupled plasma mass spectrometry (ICP-MS)
WARNING — Persons using this document should be familiar with usual 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 and to ensure
compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted according to this document be carried
out by suitably trained staff.
1 Scope
This document specifies a method for the determination of the following elements in aqua regia, nitric acid
or mixture of hydrochloric (HCl), nitric (HNO ) and tetrafluoroboric (HBF )/hydrofluoric (HF) acid digests
3 4
of soil, treated biowaste, waste, sludge and sediment:
Aluminium (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), bismuth (Bi), boron (B),
cadmium (Cd), calcium (Ca), cerium (Ce), caesium (Cs), chromium (Cr), cobalt (Co), copper (Cu),
dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), gallium (Ga), germanium (Ge), gold (Au),
hafnium (Hf), holmium (Ho), indium (In), iridium (Ir), iron (Fe), lanthanum (La), lead (Pb), lithium (Li),
lutetium (Lu), magnesium (Mg), manganese (Mn), mercury (Hg), molybdenum (Mo), neodymium (Nd),
nickel (Ni), palladium (Pd), phosphorus (P), platinum (Pt), potassium (K), praseodymium (Pr), rhenium (Re),
rhodium (Rh), rubidium (Rb), ruthenium (Ru), samarium (Sm), scandium (Sc), selenium (Se), silicon (Si),
silver (Ag), sodium (Na), strontium (Sr), sulfur (S), tellurium (Te), terbium (Tb), thallium (Tl), thorium (Th),
thulium (Tm), tin (Sn), titanium (Ti), tungsten (W), uranium (U), vanadium (V), ytterbium (Yb), yttrium (Y),
zinc (Zn), and zirconium (Zr).
The working range depends on the matrix and the interferences encountered.
The method detection limit of the method is between 0,1 mg/kg dry matter and 2,0 mg/kg dry matter
for most elements. The limit of detection will be higher in cases where the determination is likely to be
interfered (see Clause 4) or in case of memory effects (see e.g. EN ISO 17294-1).
The method has been validated for the elements given in Table A.1 (sludge), Table A.2 (compost) and
Table A.3 (soil). The method is applicable for the other elements listed above, provided the user has verified
the applicability.
This method is also applicable for the determination of major, minor and trace elements in aqua regia and
[2]
nitric acid digests and in eluates of construction products (EN 17200) .
NOTE Construction products include e.g. mineral-based products; bituminous products; metals; wood-based
products; plastics and rubbers; sealants and adhesives; paints and coatings.
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.
EN ISO 17294-1, Water quality — Application of inductively coupled plasma mass spectrometry (ICP-MS) —
Part 1: General guidelines
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ISO/DIS 16965:2024(en)
3 Principle
Digests of soil, treated biowaste, waste, sludge and sediments with nitric acid, aqua regia (see EN 16173, and
EN ISO 54321) or hydrochloric (HCl), nitric (HNO ) and tetrafluoroboric (HBF ) or hydrofluoric (HF) acid
3 4
mixture (EN 13656) are analysed by ICP-MS to get a multi-elemental determination of analytes.
The method measures ions produced by a radiofrequency inductively coupled plasma. Analyte species
originating in the digest solution are nebulised and the resulting aerosol is transported by argon gas into
the plasma. The ions produced by the high temperatures of the plasma are entrained in the plasma gas and
introduced, by means of an interface, into a mass spectrometer, sorted according to their mass-to-charge
ratios and quantified with a detector (e.g. channel electron multiplier).
NOTE For the determination of tin only aqua regia extraction applies (e.g., EN ISO 54321, EN 13656).
NOTE When tetrafluoroboric (HBF ) is used in the acid mixture, boron cannot be determined.
4 Interferences
4.1 General
Interferences shall be assessed, and valid corrections applied. Interference correction shall include compensation
for background ions contributed by the plasma gas, reagents, and constituents of the sample matrix.
Detailed information on spectral and non-spectral interferences is given in EN ISO 17294-1.
4.2 Spectral interferences
4.2.1 Isobaric elemental interferences
Isobaric elemental interferences are caused by isotopes of different elements of closely matched nominal
mass-to-charge ratio and which cannot be separated due to an insufficient resolution of the mass
114 114
spectrometer in use (e.g. Cd and Sn).
Element interferences from isobars can be corrected by considering the influence from the interfering
element (see EN ISO 17294-1). The isotopes used for correction shall be free of interference if possible.
Correction options are often included in the software supplied with the instrument. Common isobaric
interferences are given in Table B.1.
4.2.2 Isobaric molecular and doubly-charged ion interferences
Isobaric molecular and doubly-charged ion interferences in ICP-MS are caused by ions consisting of more
40 35 + 40 35 + 75
than one atom or charge, respectively. Examples include Ar Cl and Ca Cl ion on the As signal or
98 16 + 114 +
Mo O ions on the Cd signal. Natural isotope abundances are available from the literature.
The accuracy of correction equations is based upon the constancy of the observed isotopic ratios for the
interfering species. Corrections that presume a constant fraction of a molecular ion relative to the "parent"
ion have not been found to be reliable, e.g. oxide levels can vary with operating conditions. If a correction for
an oxide ion is based upon the ratio of parent-to-oxide ion intensities, this shall be determined by measuring
the interference solution just before the sequence is started. The validity of the correction coefficient should
be checked at regular intervals within a sequence.
Another possibility to remove isobaric molecular interferences is the use of an instrument with collision/
reaction cell technology and further extended to triple quadrupole technology facilitating an even more
effective use of reactive gases for interference removal. The use of high resolution ICP-MS allows the
resolution of these interferences and additionally double-charged ion interferences.
The response of the analyte of interest shall be corrected for the contribution of isobaric molecular and
doubly charged interferences if their impact can be higher than three times the detection limit or higher
than half the lowest concentration to be reported.

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ISO/DIS 16965:2024(en)
More information about the use of correction factors is given in EN ISO 17294-1.
4.2.3 Non-spectral interferences
Physical interferences are associated with sample nebulisation and transport processes as well as with
ion-transmission efficiencies. Nebulisation and transport processes can be affected if a matrix component
causes a change in surface tension or viscosity. Changes in matrix composition can cause significant signal
suppression or enhancement. Solids can be deposited on the nebuliser tip of a pneumatic nebuliser and on
the cones.
It is recommended to keep a low level of total dissolved solids, to minimise deposition of solids in the
sample introduction system of the plasma torch. An internal standard can be used to correct for physical
interferences if it is carefully matched to the analyte, so that the two elements are similarly affected by
matrix changes. Other possibilities to minimise non-spectral interferences are matrix matching, particularly
matching of the acid concentration, and standard addition.
When intolerable physical interferences are present in a sample, a significant suppression of the internal
standard signals (to less than 30 % of the signals in the calibration solution) will be observed. Dilution of the
sample (e.g. fivefold) usually eliminates the problem.
5 Reagents
For the determination of elements at trace and ultra-trace level, the reagents shall be of adequate purity. The
concentration of the analyte or interfering substances in the reagents and the water should be negligible
compared to the lowest concentration to be determined.
-1
5.1 Water, Water with an electrical conductivity less than 0,1 mS m (equivalent to resistivity greater
than 0,01 MΩ m at 25 °C). It is recommended that the water used is obtained from a purification system that
delivers ultrapure water having a resistivity greater than 0,18 MΩ m (usually expressed by manufacturers
of water purification systems as 18 MΩ cm). For all sample preparations and dilutions.
5.2 Nitric acid, HNO , c(HNO ) ≈ 15 mol/l, w(HNO ) ≈ 65 % (m/m) to 70 % (m/m).
3 3 3
5.3 Hydrochloric acid, HCl, c(HCl) ≈ 12 mol/l, w(HCl) ≈ 35 % (m/m) to 37 % (m/m).
5.4 Tetrafluoroboric acid (HBF ), c(HBF ) ≈ 6 mol/l, w(HBF ) ≈ 38 % (m/m) to 48 % (m/m).
4 4 4
5.5 Hydrofluoric acid (HF), c(HF) ≈ 23 mol/l, w(HF) ≈ 40 % (m/m) to 45 % (m/m).
5.6 Boric acid (B(OH) ), solid
5.7 Boric acid (B(OH) ) solution, e.g. 4 % (m/m) solution
Dissolve 40 g of boric acid (5.6) in 1 l of water (5.1)
5.8 Single-element standard stock solutions
Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, K, La, Li, Lu, Mg,
Mn, Mo, Na, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, Re, Rh, Ru, S, Sb, Sc, Se, Si, Sm, Sn, Sr, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb,
Zn, Zr, ρ(element) = 10 mg/l - 10 000 mg/l each.
Preferably, nitric acid preservation should be applied in order to minimise interferences by chloropolyatomic
molecules. Bi, Hf, Hg, Mo, Sn, Sb, Te, W and Zr may need hydrochloric acid for preservation. For the
stabilisation of some elements, e.g. Sb, the addition of hydrofluoric acid may be needed.
Both single-element standard stock solutions and multi-element standard stock solutions with adequate
specification stating the acid used and the preparation technique are commercially available.

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ISO/DIS 16965:2024(en)
These solutions are considered to be stable for more than one year, but in reference to guaranteed stability,
the recommendations of the manufacturer should be considered.
5.9 Anion standard stock solutions
− 3− 2−
Cl , PO , SO , ρ(anion) = 1 000 mg/l each.
4 4
Prepare these solutions from the respective acids. The solutions are commercially available.
These solutions are considered to be stable for more than one year, but in reference to guaranteed stability,
the recommendations of the manufacturer should be considered.
5.10 Multi-element standard stock solutions
Depending on the analytes to be determined, different multi-element standard stock solutions may be
necessary. In general, when combining multi-element standard stock solutions, their chemical compatibility
and the possible hydrolysis of the components shall be regarded. Care shall be taken to prevent chemical
reactions (e.g. precipitation).
The multi-element standard stock solutions are considered to be stable for several months if stored in
the dark. This does not apply to multi-element standard stock solutions that are prone to hydrolysis, in
particular solutions of e.g. Bi, Mo, Sn, Sb, Te, W, Hf and Zr.
Mercury standard stock solutions can be stabilised by adding 1 mg/l Au in nitric acid (5.2) or by adding
hydrochloric acid (5.3) up to 0,6 % (v/v).
Multi-element standard stock solutions with more elements are allowed, provided that these solutions are
stable and that the recommendations of the manufacturer are considered.
The following examples of multi-element standard stock solutions can be considered:
— Multi-element standard stock solution at the mg/l level in nitric acid containing the following elements:
Ag, Al, As, B, Ba, Be, Bi, Cd, Ce, Co, Cr, Cu, Fe, Hg, Li, Mn, Nd, Ni, Pb, Pr, Sc, Se, Si, Sm, Sr, Te, Th, Ti, Tl, U, V, Zn.
— Multi-element standard stock solution at the mg/l level in hydrochloric acid containing the following
elements: Mo, Sb, Si, Sn, W, Zr.
— Multi-element standard stock solution at the mg/l level in nitric acid containing the following elements:
Ca, Mg, Na, K, P, S.
5.11 Multi-element calibration solutions
Prepare in one or more steps calibration solutions at the highest concentration of interest. If more
concentration levels are needed prepare those similarly.
Add acids (5.2, 5.3, 5.4, 5.5 and/or 5.7) to match the acid concentration of samples closely.
If traceability of the values is not established check the validity by comparison with a (traceable) independent
standard.
Check the stability of the calibration solutions.
5.12 Internal standard solution
Internal standards can either be added to every flask or added online. It is essential that the same
concentration of internal standard is added to all measurement solutions. The following elements are among
the most often used: Li, Be, Sc, Ga, Ge, Y, Rh, In, Cs, Pr, Tb, Ho, Re, Ir, Bi, and Th.
The choice of elements for the internal standard solution depends on the analytical problem. The solution
of this/these internal standard(s) should cover the mass range of interest. The internal standards elements

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ISO/DIS 16965:2024(en)
shall not be analytes and the concentrations of the selected elements should be negligibly low in the digests
of samples.
Generally, a suitable final concentration of the internal standard in samples and calibration solutions is
1 µg/l to 50 µg/l (for a high and stable count rate). The use of a collision/reaction cell can require higher
concentrations.
NOTE For the determination of mercury (Hg), it is recommended to add a gold (Au) solution in diluted HCl to
the internal standard solution to allow a final concentration of at least 50 µg/l in the solution to be measured
[ρ(Au) ≥ 50 µg/l]. Alternatively, if Au needs to be determined, a KBrO solution in diluted HCl could be added to the
internal standard solution to allow a final concentration of at least 0,009 mM KBrO in the solution to be measured.
5.13 Calibration blank solution
Prepare the calibration blank solution by diluting acids (5.2, 5.3, 5.4, 5.5 and/or 5.7) with water (5.1) to the
same concentrations as used in the calibration solutions and test solutions.
5.14 Test blank solution
The test blank solution shall contain all of the reagents in the same concentrations and shall be handled
in the same way throughout the procedure as the samples. The test blank solution contains the same acid
concentration in the final solution as the test solution after the digestion method is applied.
5.15 Optimisation solution
The optimisation solution is used for mass calibration and for optimisation of the instrumental settings, e.g.
adjustment of maximal sensitivity with respect to minimal oxide formation rate and minimal formation of
doubly charged ions. It should contain elements covering the total mass range, as well as elements prone to
a high oxide formation rate or to the formation of doubly charged ions. The composition of the optimisation
solution depends on the elements of interest, instrument and manufacturer's instructions. An optimisation
solution containing e.g. Mg, Cu, Rh, In, Ba, La, Ce, U and Pb is suitable. Li, Be and Bi are less suitable because
they tend to cause memory effects at higher concentrations.
The mass concentrations of the elements used for optimisation should allow count rates of more than
10 counts per second.
5.16 Interference check solution
The interference check solutions are used to determine the corresponding factors for the correction
equations. High demands are made concerning the purity of the basic reagents due to the high mass
concentrations.
Interference check solutions shall contain all the interferences of practical relevance given in EN ISO 17294-1,
at a concentration level at the same range as expected in the samples (see also 10.4).
Leaving out an interfering element according to EN ISO 17294-1 is permitted if it can be demonstrated that
its impact is negligible and lasting.
In unusual situations, the other interfering elements according to EN ISO 17294-1 shall also be investigated
for relevance.
EXAMPLE An example of the composition of an interference check solution is:
− 3− 2−
ρ(Ca) = 2 500 mg/l; ρ(Cl ) = 2 000 mg/l; ρ(PO ) = 500 mg/l and ρ(SO ) = 500 mg/l
4 4
and for digests also
ρ(C) = 1 000 mg/l; ρ(Fe) = 500 mg/l; ρ(Na) = 500 mg/l and ρ(Al) = 500 mg/l.

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ISO/DIS 16965:2024(en)
6 Apparatus
6.1 General requirements
The stability of samples, measuring, and calibration solutions depends to a high degree on the container
material. The material shall be checked according to the specific purpose. For the determination of elements
in a very low concentration range (< 1 µg/kg), glass or polyvinyl chloride (PVC) should not be used. Instead,
it is recommended that perfluoroalkoxy alkane (PFA), hexafluoroethene propene (FEP) or quartz containers,
cleaned with diluted, high quality nitric acid or hot, concentrated nitric acid in a closed system be used.
For the determination of elements in a higher concentration range, containers made from high density
polyethylene (HDPE) or polytetrafluoroethene (PTFE) are also suited for the collection of samples.
The limit of detection of most elements is affected by contamination of solutions and this depends
predominantly on the cleanliness of laboratory air.
The use of piston pipettes is permitted and enables the preparation of smaller volumes of calibration
solutions. The application of dilutors is also allowed. Every charge of pipette tips and single-use plastics
vessels shall be tested for impurities.
For more detailed information on the instrumentation see EN ISO 17294-1.
6.2 Mass spectrometer
A mass spectrometer with inductively coupled plasma (ICP) suitable for multi-element and isotope analysis
is required. The spectrometer should be capable of scanning a mass range from 5 m/z (amu) to 240 m/z
(amu) with a resolution of at least 1 mr/z peak width at 5 % of peak height (mr = relative mass of an atom
species; z = charge number). The instrument may be fitted with a conventional or extended dynamic range
detection system.
Quadrupole ICP-MS, collision/reaction cell ICP-MS, triple quadrupole ICP-MS, high-resolution ICP-MS and
time-of-flight ICP-MS instrumentation are suitable for measurement.
6.3 Mass-flow controller
A mass-flow controller on the nebuliser gas supply is strongly recommended. Mass-flow controllers for the
plasma gas and the auxiliary gas are preferred. A cooled spray chamber (cold water or Peltier element) may
be beneficial in reducing some types of interferences (e.g. from polyatomic oxide species).
6.4 Nebuliser with variable speed peristaltic pump
The speed of the pump shall not be too low and the number of rolls as high as possible to provide a stable
signal. The quantity of solution that is pumped is mostly between 0,1 ml and 1,0 ml per minute and typically
around 0,4-0,5 ml per minute.
6.5 Gas supply
6.5.1 Argon, Ar, with high purity grade, i.e. > 99,99 %.
6.5.2 Reaction gas, e.g. Helium (He), Hydrogen (H ), Oxygen (O ), ammonia gas (NH ), or methane (CH )
2 2 3 4
with high purity grade, i.e. > 99,99 %.
6.6 Storage bottles for the stock, standard, calibration and sample solutions.
Preferably made from perfluoroalkoxy alkane (PFA) or hexafluoroethene propene (FEP). For the
determination of elements in a higher concentration range (> 1 µg/kg), high density polyethylene (HDPE) or
polytetrafluoroethene (PTFE) bottles may be suitable.

oSIST prEN ISO 16965:2024
ISO/DIS 16965:2024(en)
7 Procedure
7.1 Test sample solution
The test sample solution is a particle-free digest or extraction solution prepared according to, e.g., EN 16173,
EN 13656 or EN ISO 54321.
7.2 Test solution
The test solution is an aliquot of the test sample solution and can be directly obtained from the test sample
solution or can be diluted to accommodate the measurement range or to dilute the matrix.
The acidity of calibration solutions shall match the acid concentration in test solutions.
Ensure that all elements are present in a non-volatile form. Volatile species shall be converted to non-volatile
ones, e.g. sulfide oxidation by hydrogen peroxide.
7.3 Instrument set-up
Adjust the instrumental parameters of the ICP-MS system in accordance with the manufacturer’s
instructions. A guideline for method and instrument set up is given in EN ISO 17294-1.
Define the isotopes and the need for corresponding corrections. See EN ISO 17294-1, for a method to
determine these factors. Alternatively, apply multivariate calibration procedures.
Define the rinsing times depending on the length of the flow path; in the case of wide working range of
analyte mass concentrations in the measuring solutions, allow longer rinsing periods.
The use of an internal standard is mandatory. Add the internal standard solution (5.12) to the interference
check solution (5.16), to all multi-element calibration solutions (5.11), to the calibration blank solutions
(5.13), and to all measuring solutions.
NOTE 1 Online dilution and mixing of the sample flow with internal standard solution by means of the peristaltic
pump of the nebuliser is commonly used. In such cases, the calibration solutions are diluted the same way as the
sample solutions.
The mass concentration of the internal standard elements shall be the same in all solutions. Generally, a
suitable concentration of the internal standard element in sample and calibration solutions is 10 µg/l to
50 µg/l (for a high and stable count rate, at least 50 000 – 100 000 counts/s).
Adjust the instrument to working condition. This takes usually 30 min.
Before each series of measurements check the sensitivity and the stability of the system and minimise
interferences, e.g. by using the optimisation solution (5.15).
Check the resolution and the mass calibration as often as required by the manufacturer.
NOTE 2 ICP-MS has excellent multi-element capability. Nevertheless, it does not mean that all elements can be
analysed under optimal conditions during one measurement run. The sensitivity of determination depends on
numerous parameters (nebuliser flow, radio-frequency power, lens voltage, lens voltage mode etc.). Depending on the
analytical requirements, optimal instrument settings must be chosen.
7.4 Calibration
7.4.1 Linear calibration function
ICP-MS provides a large linear measurement range. The linearity over a broad concentration range shall
be checked for setting the calibration range. Satisfying results are obtained with a two-point calibration: a
blank calibration solution and a calibration solution for the upper point of the measurement range. However,
multiple calibration solutions (a minimum of four calibration standards plus a blank calibration) are
recommended in case of a more orders of magnitude measurement range. The calibration function is only

oSIST prEN ISO 16965:2024
ISO/DIS 16965:2024(en)
valid under specific operational conditions and should be re-established if these conditions are changed.
After the failure of a control sample it is sufficient to recalibrate with minimum 2 points and perform a
calibration check (10.2).
Multi-level calibration and standard least-squares fitting can lead to wrong results because of the
inhomogeneity of the variances of the measurements of the calibration solutions over the concentration
range. This approach leads to errors at the low end of the calibration curve, unless weighed linear regression
is used instead of the standard least-squares fitting. Weighed linear regression is based on the principle that
the weighing factor is inversely proportional to the standard deviation of the measurement of the calibration
solution.
7.4.2 Standard addition calibration
Add a known amount of standard solution of the analyte and an equal amount of blank solution to two
separate but equal portions of the sample solution (or its dilution). Minimise dilution or correct for spike
dilution. The added amount of standard solution should be between 0,4 times and 2 times the expected
sample mass concentration. Measure both solutions as a sample solution. Determine the ‘measured spike
concentration' as the difference in mass concentration between the two spiked sample portions. Use the
ratio ‘true spike concentration’ versus ‘measured spike concentration’ as a correction factor for the initially
measured concentration of the sample portion.
7.4.3 Determination of correction factors
The need for the use of correction factors is determined during method development but became obsolete
since the introduction of collision reaction cell whether in combination with triple quadrupole technology.
Correction factors should be evaluated and updated, for example by measuring interference check solutions
(5.16) at regular intervals within a sequence.
40 35 + 75
NOTE For example the interference correction factor for Ar Cl on As is determined by recording the signal
−
at mass 75 and 35 of a Cl solution; the ratio of the net signal at mass 75 and net signal at mass 35 is the correction
98 16 +
factor. For the isobaric molecular interference of Mo O the correction factor is determined by the recording of the
signal at mass 114 and 98 of a Mo solution.
7.4.4 Variable isotope ratio
Take into account the possible discrepancies in the isotope composition between the calibration solut
...