Infant formula and adult nutritionals -Determination of total iodine - Inductively coupled plasma mass spectrometry (ICP-MS) (ISO 20647:2015)

ISO 20647:2015 specifies a method for the quantitative determination of total iodine in infant formula and adult nutritional formula.[1] The method is applicable to the measurement of total iodine in infant formula and adult nutritional formula from 0,5 µg/100g to 1 500 µg/100g reconstituted final product and for ready-to-feed products from 2,5 µg/100 g to 1 000 µg/100 g using ICP-MS.
Using various infant formula and adult nutritional products, the method was subjected to an interlaboratory study. Levels obtained ranged from 3,47 µg/100 g to 124 µg/100 g. For all precision data related to the interlaboratory study, see Table A.1 located in Annex A.

Säuglingsanfangsnahrung und Nahrungsergänzungsmittel für Erwachsene - Bestimmung des Gesamtiods - Massenspektrometrie mit induktiv gekoppeltem Plasma (ICP-MS) (ISO 20647:2015)

Formules infantiles et produits nutritionnels pour adultes - Détermination de la teneur en iode total - Spectrométrie de masse avec plasma à couplage inductif (ICP-SM) (ISO 20647:2015)

ISO 20647:2015 spécifie une méthode de détermination quantitative de la teneur en iode total dans les formules infantiles et produits nutritionnels pour adultes[1]. La méthode s'applique au dosage de l'iode total dans les formules infantiles et dans les produits nutritionnels pour adultes entre 0,5 µg/100 g et 1 500 µg/100 g de produit final reconstitué et dans les produits prêts à servir entre 2,5 µg/100 g et 1 000 µg/100 g par ICP-SM.
La méthode a fait l'objet d'une étude interlaboratoires en utilisant diverses formules infantiles et produits nutritionnels pour adultes. Les niveaux obtenus variaient de 3,47 µg/100 g à 124 µg/100 g. Pour toutes les données de fidélité liées à l'étude interlaboratoires, voir le Tableau A.1.

Hrana za dojenčke in prehranska dopolnila za odrasle - Določevanje celotnega joda - Masna spektrometrija z induktivno sklopljeno plazmo (ICP-MS) (ISO 20647:2015)

General Information

Status
Published
Public Enquiry End Date
19-Mar-2020
Publication Date
18-Jun-2020
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
11-Jun-2020
Due Date
16-Aug-2020
Completion Date
19-Jun-2020

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SLOVENSKI STANDARD
SIST EN ISO 20647:2020
01-julij-2020
Hrana za dojenčke in prehranska dopolnila za odrasle - Določevanje celotnega
joda - Masna spektrometrija z induktivno sklopljeno plazmo (ICP-MS) (ISO
20647:2015)
Infant formula and adult nutritionals -Determination of total iodine - Inductively coupled
plasma mass spectrometry (ICP-MS) (ISO 20647:2015)
Säuglingsanfangsnahrung und Nahrungsergänzungsmittel für Erwachsene -
Bestimmung des Gesamtiods - Massenspektrometrie mit induktiv gekoppeltem Plasma
(ICP-MS) (ISO 20647:2015)
Formules infantiles et produits nutritionnels pour adultes - Détermination de la teneur en
iode total - Spectrométrie de masse avec plasma à couplage inductif (ICP-SM) (ISO
20647:2015)
Ta slovenski standard je istoveten z: EN ISO 20647:2020
ICS:
67.050 Splošne preskusne in General methods of tests and
analizne metode za živilske analysis for food products
proizvode
67.230 Predpakirana in pripravljena Prepackaged and prepared
hrana foods
SIST EN ISO 20647:2020 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 20647:2020

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SIST EN ISO 20647:2020


EN ISO 20647
EUROPEAN STANDARD

NORME EUROPÉENNE

June 2020
EUROPÄISCHE NORM
ICS 67.050
English Version

Infant formula and adult nutritionals -Determination of
total iodine - Inductively coupled plasma mass
spectrometry (ICP-MS) (ISO 20647:2015)
Formules infantiles et produits nutritionnels pour Säuglingsanfangsnahrung und
adultes - Détermination de la teneur en iode total - Nahrungsergänzungsmittel für Erwachsene -
Spectrométrie de masse avec plasma à couplage Bestimmung des Gesamtiods - Massenspektrometrie
inductif (ICP-SM) (ISO 20647:2015) mit induktiv gekoppeltem Plasma (ICP-MS) (ISO
20647:2015)
This European Standard was approved by CEN on 10 May 2020.

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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20647:2020 E
worldwide for CEN national Members.

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SIST EN ISO 20647:2020
EN ISO 20647:2020 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 20647:2020
EN ISO 20647:2020 (E)
European foreword
The text of ISO 20647:2015 has been prepared by Technical Committee ISO/TC 34 "Food products” of
the International Organization for Standardization (ISO) and has been taken over as EN ISO 20647:2020
by Technical Committee CEN/TC 302 “Milk and milk products - Methods of sampling and analysis” the
secretariat of which is held by NEN.
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 December 2020, and conflicting national standards
shall be withdrawn at the latest by December 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 20647:2015 has been approved by CEN as EN ISO 20647:2020 without any modification.

3

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SIST EN ISO 20647:2020

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SIST EN ISO 20647:2020
INTERNATIONAL ISO
STANDARD 20647
IDF
234
First edition
2015-11-01
Infant formula and adult
nutritionals — Determination of total
iodine — Inductively coupled plasma
mass spectrometry (ICP-MS)
Formules infantiles et produits nutritionnels pour adultes —
Détermination de la teneur en iode total — Spectrométrie de masse
avec plasma à couplage inductif (ICP-SM)
Reference numbers
ISO 20647:2015(E)
IDF 234:2015(E)
©
ISO and IDF 2015

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SIST EN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO and IDF 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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 International Dairy Federation
Ch. de Blandonnet 8 • CP 401 Silver Building • Bd Auguste Reyers 70/B • B-1030 Brussels
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11 Tel. + 32 2 325 67 40
Fax +41 22 749 09 47 Fax + 32 2 325 67 41
copyright@iso.org info@fil-idf.org
www.iso.org www.fil-idf.org
ii © ISO and IDF 2015 – All rights reserved

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SIST EN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Contents Page
Forewords .iv
1 Scope . 1
2 Principle . 1
3 Reagents and materials . 1
4 Apparatus . 5
5 Procedure. 6
5.1 Reconstitution . 6
5.2 Sample preparation . 6
5.3 Addition of reagents . 7
5.4 Oven digestion . 7
5.5 Open vessel microwave digestion . 7
5.6 Sample filtering . 8
5.7 Sample dilution . 8
5.8 Determination . 8
5.9 Conditioning . 9
5.10 Calibration . 9
5.11 Sample analysis . 9
5.12 Data acceptability .10
6 Calculation .10
7 Precision .11
7.1 Interlaboratory tests .11
7.2 Repeatability .11
7.3 Reproducibility .11
Annex A (informative) Precision data .12
Bibliography .13
© ISO and IDF 2015 – All rights reserved iii

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SIST EN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Forewords
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 wit the
editorial rules of 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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 34, Food products, Subcommittee SC 5, Milk and
milk products and the International Dairy Federation (IDF), in collaboration with AOAC INTERNATIONAL.
It is being published jointly by ISO and IDF and separately by AOAC INTERNATIONAL. The method
described in this International Standard is equivalent to the AOAC Official Method 2012.15: Total iodine
in infant formula and adult/pediatric nutritional formula – inductively coupled plasma-mass spectrometry.
iv © ISO and IDF 2015 – All rights reserved

---------------------- Page: 10 ----------------------
SIST EN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
IDF (the International Dairy Federation) is a non-profit private sector organization representing the
interests of various stakeholders in dairying at the global level. IDF members are organized in National
Committees, which are national associations composed of representatives of dairy-related national
interest groups including dairy farmers, dairy processing industry, dairy suppliers, academics and
governments/food control authorities.
ISO and IDF collaborate closely on all matters of standardization relating to methods of analysis
and sampling for milk and milk products. Since 2001, ISO and IDF jointly publish their International
Standards using the logos and reference numbers of both organizations.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. IDF 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 and endorsement.
ISO 20647 | IDF 234 was prepared by the IDF Standing Committee on Analytical Methods for
Composition and the ISO Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and
milk products, in collaboration with AOAC INTERNATIONAL. It is being published jointly by ISO and
IDF, and separately by AOAC INTERNATIONAL. The method described in this International Standard
is equivalent to the AOAC Official Method 2012.15: Total iodine in infant formula and adult/pediatric
nutritional formula – inductively coupled plasma-mass spectrometry.
All work was carried out by the ISO-IDF Project Group C37 of the Standing Committee on Analytical
Methods for Composition under the aegis of its project leader, Mr Erik Konings (CH).
© ISO and IDF 2015 – All rights reserved v

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SIST EN ISO 20647:2020

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SIST EN ISO 20647:2020
ISO 20647:2015(E)
INTERNATIONAL STANDARD
IDF 234:2015(E)
Infant formula and adult nutritionals — Determination
of total iodine — Inductively coupled plasma mass
spectrometry (ICP-MS)
WARNING — The use of this International Standard can involve hazardous materials, operations
and equipment. This International Standard does not purport to address all the safety problems
associated with its use. It is the responsibility of the user of this International Standard to
establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1 Scope
This International Standard specifies a method for the quantitative determination of total iodine in
[1]
infant formula and adult nutritional formula. The method is applicable to the measurement of total
iodine in infant formula and adult nutritional formula from 0,5 µg/100g to 1 500 µg/100g reconstituted
final product and for ready-to-feed products from 2,5 µg/100 g to 1 000 µg/100 g using ICP-MS.
Using various infant formula and adult nutritional products, the method was subjected to an
interlaboratory study. Levels obtained ranged from 3,47 µg/100 g to 124 µg/100 g. For all precision
data related to the interlaboratory study, see Table A.1 located in Annex A.
2 Principle
Digestion occurs using a potassium hydroxide (KOH) solution in an oven or open-vessel microwave
system. Iodine is stabilized with ammonium hydroxide and sodium thiosulfate after digestion. The
solution is brought to volume followed by filtration. The filtrate is analysed directly or after dilution by
inductively coupled plasma mass spectrometry (ICP-MS).
3 Reagents and materials
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and
distilled or demineralized water or water of equivalent purity. Equivalent chemicals and reagents may
be used.
1)
3.1 KOH pellets, certified ACS grade, e.g. Fisher Scientific, Fairlawn, NJ .
NOTE KOH may contribute background levels of iodine.
1)
3.2 Ammonium hydroxide (NH OH), 28 % to 30 % (m/m), certified ACS PLUS, Fisher Scientific .
4
1)
3.3 Sodium thiosulfate (Na S O ), purity ≥ 99,99 %, metal basis, Fisher Scientific .
2 2 3
® 1)
3.4 Surfactant, e.g. Triton X-100, Sigma, St. Louis, MO .
1)
3.5 Concentrated nitric acid (HNO ), Optima, high purity, Fisher Scientific .
3
3.6 Perchloric acid (HClO ), 70 % (m/m).
4

1) This is an example of a suitable product available commercially. This information is given for the convenience
of users of this document and does not constitute an endorsement by either ISO or IDF of the product named.
Equivalent products may be used if they can be shown to lead to the same results.
© ISO and IDF 2015 – All rights reserved 1

---------------------- Page: 13 ----------------------
SIST EN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
3.7 Purified water, 18 MΩ/cm.
3.8 Reference standards
1)
3.8.1 Iodide standard solution in water, mass concentration ρ = 1 000 µg/ml, SPEX CertiPrep .
1)
3.8.2 Iodide standard solution in 1 % triethylamine (TEA), ρ = 1 000 µg/ml, Inorganic Ventures .
3.8.3 Standard Reference Material (SRM), National Institute of Standards and Technology (NIST) SRM
1849a, Infant/Adult Nutritional Formula.
Either stock iodide reference solutions may be used for intermediate and working standard solutions
preparation. The remaining source may be used as a continuing calibration verification (CCV) standard.
Equivalent reference standards may be substituted. ‘Iodide’ may be referred to as ‘iodine’ throughout
this International Standard.
3.9 Internal standards
1)
3.9.1 Praseodymium (Pr) standard solution in 5 % HNO , ρ = 10 µg/ml, Inorganic Ventures .
3
Individual values of iodine are reported for each test sample using praseodymium as the internal
standard. Equivalent stock internal standard solutions may be substituted.
3.10 Preparation of reagent solutions
3.10.1 General
Prepare all reagent solutions as recommended by either mass per volume or volume per volume.
Adjusting for purity and/or concentration is not required.
3.10.2 KOH solution, ρ = 50 g/l
Dissolve 25 g of KOH pellets in an appropriate amount of purified water, then dilute to 500 ml with
purified water. This solution may be added using a re-pipet volumetric bottle top dispenser. Store this
solution at room temperature. Reagent expires 6 months after preparation date.
3.10.3 Stabilizer concentrate
Dissolve 5 g of Na S O in an appropriate amount of purified water, add 50 ml of NH OH, then dilute to
2 2 3 4
500 ml with purified water. The resulting concentration is 10 % NH OH and 1 % Na S O in purified
4 2 2 3
water. Store this solution at room temperature. Reagent expires 6 months after preparation date.
3.10.4 Wash solution (rinse)
Dissolve 2 g of surfactant (3.4) in an appropriate amount of purified water, add 20 ml of NH OH, then
4
dilute to 2 000 ml with purified water. The resulting concentration is 1 % NH OH and 0,1 % surfactant
4
in purified water. This solution may be added using a re-pipet volumetric bottle top dispenser. Store
this solution at room temperature. Reagent expires 6 months after preparation date.
3.10.5 Diluent
Dissolve 10 g of KOH pellets and 0,4 g Na S O in an appropriate amount of purified water, add 4 ml
2 2 3
NH OH, then dilute to 2 000 ml with purified water. Store this solution at room temperature. Reagent
4
expires 6 months after preparation date.
2 © ISO and IDF 2015 – All rights reserved

---------------------- Page: 14 ----------------------
SIST EN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Alternatively, for a smaller volume, dilute 50 ml of 5 % KOH and 10 ml of stabilizer concentrate (3.10.3)
to 500 ml with purified water. The resulting concentrations for both preparations are 0,5 % KOH, 0,2 %
NH OH, and 0,02 % Na S O in purified water. Store this solution at room temperature. Reagent expires
4 2 2 3
6 months after preparation date.
3.10.6 Conditioning solution
Prepare by aliquoting 25 ml of KOH solution (3.10.2), then dilute to 250 ml with purified water. Use this
solution to prepare the instrument for analysis. The resulting concentration is 5 g/l KOH. Store this
solution at room temperature. Reagent expires 6 months after preparation date.
3.10.7 Carrier solution
This solution is equivalent to the wash solution (3.10.4). The carrier solution is used to deliver the sample
solution to the nebulizer through the ICP-MS autosampler introduction system. The carrier solution is
introduced via a peristaltic pump using 0,76 mm inside diameter (id) two-stop polyvinyl chloride pump
tubing. Store this solution at room temperature. Reagent expires 6 months after preparation date.
3.11 Preparation of standard solutions
3.11.1 General
Stock solutions are stable until the end date indicated on the certificate of analysis. Intermediate stock
standard, calibration standard, continuing calibration verification and internal standard solutions
are stable at room temperature until the earliest expiration date of all components used to prepare
the solution. These solutions are ready to use for analysis. Do not subject them to any of the various
procedures used to prepare actual samples (i.e. infant formulas and adult nutritionals) for analysis.
3.11.2 Stock iodine and praseodymium solutions
Purchase of stock iodine and praseodymium standard solutions with accompanying certificates of
analysis is recommended.
3.11.3 Intermediate stock standard (ISS) iodine solutions
Prepare the intermediate stock standard iodine solutions according to Table 1.
These ISS solutions are used for calibration standard preparation and are typically prepared according
to Table 1. The ISS concentrations presented are nominal. Using the stock iodine concentration found
on the certificate of analysis, determine the exact concentration of each ISS. An electronic adjustable
volume pipet, capable of delivering 100 µl to 5 000 µl should be used.
Table 1 — Preparation of intermediate stock standard (ISS) iodine solutions
Iodine standard ID of solution used for Initial iodine Aliquot volume Final Final iodine
solution ID preparation concentration ml volume concentration
ng/ml ml ng/ml
10 000 (ISS) Stock 1 000 000 0,5 50 10 000
1 000 (ISS) 10 000 (ISS) 10 000 5 50 1 000
10,0 (ISS) 1 000 (ISS) 1 000 0,5 50 10,0
Aliquot the appropriate amount of iodine standard solution into a single use 50 ml tube (4.1) and add 5 ml of stabilizer
concentrate (3.10.3), fill to the 50 ml mark on the tube with water, cap the tube and then mix thoroughly. The resulting
matrix concentration is 1 % NH OH and 0,1 % Na S O in water.
4 2 2 3
3.11.4 Calibration standard (CS) iodine solutions
Prepare the intermediate stock standard iodine solutions according to Table 2.
© ISO and IDF 2015 – All rights reserved 3

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SIST EN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Typical CS standard concentrations are nominally 0,250 ng/ml, 0,500 ng/ml, 1,00 ng/ml, 10,0 ng/ml,
50,0 ng/ml and 100 ng/ml iodine and are typically prepared according to Table 2. The calibration
2)
2)
blank is the zero point of the curve. The curve type used, if using a Perkin Elmer ICP-MS with ELAN
2) 2)
software, should be linear through zero. If using an Agilent or Thermo ICP-MS, force the curve
through the calibration blank. The calibration curve shall have a correlation coefficient (r) of ≥ 0,998
to be acceptable. Determine the exact concentration of each CS (traceable back to the certificate of
analysis) and assign these values to the curve points used to generate the final results. An electronic
adjustable volume pipet, capable of delivering 100 µl to 5 000 µl should be used.
Table 2 — Preparation of calibration standard (CS) iodine and calibration blank (CB) solutions
Iodine standard ID of solution used for Initial iodine Aliquot volume Final Final iodine
solution ID preparation concentration ml volume concentration
ng/ml ml ng/ml
100 (CS) 1 000 (ISS) 1 000 5 50 100
50,0 (CS) 1 000 (ISS) 1 000 2,5 50 50,0
10,0 (CS) 1 000 (ISS) 1 000 0,5 50 10,0
1,00 (CS) 10,0 (ISS) 10,0 5 50 1,00
0,500 (CS) 10,0 (ISS) 10,0 2,5 50 0,500
0,250 (CS) 10,0 (ISS) 10,0 1,25 50 0,250
a a a
Blank (CB) n.a. n.a. n.a. 50 0
Aliquot the appropriate amount of iodine standard solution into a single use 50 ml tube (4.1) and add 5 ml of 5 % KOH and
1 ml of stabilizer concentrate (3.10.3), fill to the 50 ml mark on the tube with water, cap the tube and then mix thoroughly.
The resulting matrix concentration is 0,5 % KOH and approximately 0,2 % NH OH and approximately 0,02 % Na S O in
4 2 2 3
water.
a
n.a. is not applicable
3.11.5 Intermediate continuing calibration verification (ICCV), continuing calibration verification
(CCV) iodine solutions and continuing calibration blank (CCB) solution
A CCV solution shall be prepared from a source other than that used for the CS solutions. For example,
2
if a stock solution from SPEX CertiPrep was used to prepare the CS solutions, do not use this same
2
solution to prepare the CCV solution. Instead use a stock solution from Inorganic Ventures (or another
suitable manufacturer) to prepare the CCV solution.
Prepare the intermediate continuing calibration verification, continuing calibration verification
standards solutions and continuing calibration blank according to Table 3.
ICCV solutions are used for preparation of the CCV standard solution and are typically prepared
according to Table 3. The ICCV and CCV concentrations presented are nominal. Using the stock iodine
concentration found on the certificate of analysis (from the second source), determine the exact
concentration of each ICCV. With this information, determine the exact concentration of the CCV
standard. An electronic adjustable volume pipet, capable of delivering 100 µl to 5 000 µl should be used.

2) This is an example of a suitable product available commercially. This information is given for the convenience
of users of this document and does not constitute an endorsement by either ISO or IDF of the product named.
Equivalent products may be used if they can be shown to lead to the same results.
4 © ISO and IDF 2015 – All rights reserved

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SIST EN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Table 3 — Preparation of intermediate continuing calibration verification (ICCV), continuing
calibration verification (CCV) iodine solutions and continuing calibration blank (CCB) solution
Iodine standard ID of solution used for Initial iodine Aliquot volume Final Final iodine
solution ID preparation concentration ml volume concentration
ng/ml ml ng/ml
10 000 (ICCV) Stock 1 000 000 0,5 50 10 000
1 000 (ICCV) 10 000 (ICCV) 10 000 5 50 1 000
10,0 (CCV) 1 000 (ICCV) 1 000 0,5 50 10,0
a a a
Blank (CCB) n.a. n.a. n.a. 50 0
Aliquot the appropriate amount of iodin
...

SLOVENSKI STANDARD
oSIST prEN ISO 20647:2020
01-marec-2020
Hrana za dojenčke in prehranska dopolnila za odrasle - Določevanje celotnega
joda - Masna spektrometrija z induktivno sklopljeno plazmo (ICP-MS) (ISO
20647:2015)
Infant formula and adult nutritionals -Determination of total iodine - Inductively coupled
plasma mass spectrometry (ICP-MS) (ISO 20647:2015)
Säuglingsanfangsnahrung und Nahrungsergänzungsmittel für Erwachsene -
Bestimmung des Gesamtiods - Massenspektrometrie mit induktiv gekoppeltem Plasma
(ICP-MS) (ISO 20647:2015)
Formules infantiles et produits nutritionnels pour adultes - Détermination de la teneur en
iode total - Spectrométrie de masse avec plasma à couplage inductif (ICP-SM) (ISO
20647:2015)
Ta slovenski standard je istoveten z: prEN ISO 20647
ICS:
67.050 Splošne preskusne in General methods of tests and
analizne metode za živilske analysis for food products
proizvode
oSIST prEN ISO 20647:2020 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 20647:2020

---------------------- Page: 2 ----------------------
oSIST prEN ISO 20647:2020
INTERNATIONAL ISO
STANDARD 20647
IDF
234
First edition
2015-11-01
Infant formula and adult
nutritionals — Determination of total
iodine — Inductively coupled plasma
mass spectrometry (ICP-MS)
Formules infantiles et produits nutritionnels pour adultes —
Détermination de la teneur en iode total — Spectrométrie de masse
avec plasma à couplage inductif (ICP-SM)
Reference numbers
ISO 20647:2015(E)
IDF 234:2015(E)
©
ISO and IDF 2015

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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
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© ISO and IDF 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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the requester.
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ii © ISO and IDF 2015 – All rights reserved

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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Contents Page
Forewords .iv
1 Scope . 1
2 Principle . 1
3 Reagents and materials . 1
4 Apparatus . 5
5 Procedure. 6
5.1 Reconstitution . 6
5.2 Sample preparation . 6
5.3 Addition of reagents . 7
5.4 Oven digestion . 7
5.5 Open vessel microwave digestion . 7
5.6 Sample filtering . 8
5.7 Sample dilution . 8
5.8 Determination . 8
5.9 Conditioning . 9
5.10 Calibration . 9
5.11 Sample analysis . 9
5.12 Data acceptability .10
6 Calculation .10
7 Precision .11
7.1 Interlaboratory tests .11
7.2 Repeatability .11
7.3 Reproducibility .11
Annex A (informative) Precision data .12
Bibliography .13
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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Forewords
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 wit the
editorial rules of 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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 34, Food products, Subcommittee SC 5, Milk and
milk products and the International Dairy Federation (IDF), in collaboration with AOAC INTERNATIONAL.
It is being published jointly by ISO and IDF and separately by AOAC INTERNATIONAL. The method
described in this International Standard is equivalent to the AOAC Official Method 2012.15: Total iodine
in infant formula and adult/pediatric nutritional formula – inductively coupled plasma-mass spectrometry.
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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
IDF (the International Dairy Federation) is a non-profit private sector organization representing the
interests of various stakeholders in dairying at the global level. IDF members are organized in National
Committees, which are national associations composed of representatives of dairy-related national
interest groups including dairy farmers, dairy processing industry, dairy suppliers, academics and
governments/food control authorities.
ISO and IDF collaborate closely on all matters of standardization relating to methods of analysis
and sampling for milk and milk products. Since 2001, ISO and IDF jointly publish their International
Standards using the logos and reference numbers of both organizations.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. IDF 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 and endorsement.
ISO 20647 | IDF 234 was prepared by the IDF Standing Committee on Analytical Methods for
Composition and the ISO Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and
milk products, in collaboration with AOAC INTERNATIONAL. It is being published jointly by ISO and
IDF, and separately by AOAC INTERNATIONAL. The method described in this International Standard
is equivalent to the AOAC Official Method 2012.15: Total iodine in infant formula and adult/pediatric
nutritional formula – inductively coupled plasma-mass spectrometry.
All work was carried out by the ISO-IDF Project Group C37 of the Standing Committee on Analytical
Methods for Composition under the aegis of its project leader, Mr Erik Konings (CH).
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oSIST prEN ISO 20647:2020

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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
INTERNATIONAL STANDARD
IDF 234:2015(E)
Infant formula and adult nutritionals — Determination
of total iodine — Inductively coupled plasma mass
spectrometry (ICP-MS)
WARNING — The use of this International Standard can involve hazardous materials, operations
and equipment. This International Standard does not purport to address all the safety problems
associated with its use. It is the responsibility of the user of this International Standard to
establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1 Scope
This International Standard specifies a method for the quantitative determination of total iodine in
[1]
infant formula and adult nutritional formula. The method is applicable to the measurement of total
iodine in infant formula and adult nutritional formula from 0,5 µg/100g to 1 500 µg/100g reconstituted
final product and for ready-to-feed products from 2,5 µg/100 g to 1 000 µg/100 g using ICP-MS.
Using various infant formula and adult nutritional products, the method was subjected to an
interlaboratory study. Levels obtained ranged from 3,47 µg/100 g to 124 µg/100 g. For all precision
data related to the interlaboratory study, see Table A.1 located in Annex A.
2 Principle
Digestion occurs using a potassium hydroxide (KOH) solution in an oven or open-vessel microwave
system. Iodine is stabilized with ammonium hydroxide and sodium thiosulfate after digestion. The
solution is brought to volume followed by filtration. The filtrate is analysed directly or after dilution by
inductively coupled plasma mass spectrometry (ICP-MS).
3 Reagents and materials
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and
distilled or demineralized water or water of equivalent purity. Equivalent chemicals and reagents may
be used.
1)
3.1 KOH pellets, certified ACS grade, e.g. Fisher Scientific, Fairlawn, NJ .
NOTE KOH may contribute background levels of iodine.
1)
3.2 Ammonium hydroxide (NH OH), 28 % to 30 % (m/m), certified ACS PLUS, Fisher Scientific .
4
1)
3.3 Sodium thiosulfate (Na S O ), purity ≥ 99,99 %, metal basis, Fisher Scientific .
2 2 3
® 1)
3.4 Surfactant, e.g. Triton X-100, Sigma, St. Louis, MO .
1)
3.5 Concentrated nitric acid (HNO ), Optima, high purity, Fisher Scientific .
3
3.6 Perchloric acid (HClO ), 70 % (m/m).
4

1) This is an example of a suitable product available commercially. This information is given for the convenience
of users of this document and does not constitute an endorsement by either ISO or IDF of the product named.
Equivalent products may be used if they can be shown to lead to the same results.
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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
3.7 Purified water, 18 MΩ/cm.
3.8 Reference standards
1)
3.8.1 Iodide standard solution in water, mass concentration ρ = 1 000 µg/ml, SPEX CertiPrep .
1)
3.8.2 Iodide standard solution in 1 % triethylamine (TEA), ρ = 1 000 µg/ml, Inorganic Ventures .
3.8.3 Standard Reference Material (SRM), National Institute of Standards and Technology (NIST) SRM
1849a, Infant/Adult Nutritional Formula.
Either stock iodide reference solutions may be used for intermediate and working standard solutions
preparation. The remaining source may be used as a continuing calibration verification (CCV) standard.
Equivalent reference standards may be substituted. ‘Iodide’ may be referred to as ‘iodine’ throughout
this International Standard.
3.9 Internal standards
1)
3.9.1 Praseodymium (Pr) standard solution in 5 % HNO , ρ = 10 µg/ml, Inorganic Ventures .
3
Individual values of iodine are reported for each test sample using praseodymium as the internal
standard. Equivalent stock internal standard solutions may be substituted.
3.10 Preparation of reagent solutions
3.10.1 General
Prepare all reagent solutions as recommended by either mass per volume or volume per volume.
Adjusting for purity and/or concentration is not required.
3.10.2 KOH solution, ρ = 50 g/l
Dissolve 25 g of KOH pellets in an appropriate amount of purified water, then dilute to 500 ml with
purified water. This solution may be added using a re-pipet volumetric bottle top dispenser. Store this
solution at room temperature. Reagent expires 6 months after preparation date.
3.10.3 Stabilizer concentrate
Dissolve 5 g of Na S O in an appropriate amount of purified water, add 50 ml of NH OH, then dilute to
2 2 3 4
500 ml with purified water. The resulting concentration is 10 % NH OH and 1 % Na S O in purified
4 2 2 3
water. Store this solution at room temperature. Reagent expires 6 months after preparation date.
3.10.4 Wash solution (rinse)
Dissolve 2 g of surfactant (3.4) in an appropriate amount of purified water, add 20 ml of NH OH, then
4
dilute to 2 000 ml with purified water. The resulting concentration is 1 % NH OH and 0,1 % surfactant
4
in purified water. This solution may be added using a re-pipet volumetric bottle top dispenser. Store
this solution at room temperature. Reagent expires 6 months after preparation date.
3.10.5 Diluent
Dissolve 10 g of KOH pellets and 0,4 g Na S O in an appropriate amount of purified water, add 4 ml
2 2 3
NH OH, then dilute to 2 000 ml with purified water. Store this solution at room temperature. Reagent
4
expires 6 months after preparation date.
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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Alternatively, for a smaller volume, dilute 50 ml of 5 % KOH and 10 ml of stabilizer concentrate (3.10.3)
to 500 ml with purified water. The resulting concentrations for both preparations are 0,5 % KOH, 0,2 %
NH OH, and 0,02 % Na S O in purified water. Store this solution at room temperature. Reagent expires
4 2 2 3
6 months after preparation date.
3.10.6 Conditioning solution
Prepare by aliquoting 25 ml of KOH solution (3.10.2), then dilute to 250 ml with purified water. Use this
solution to prepare the instrument for analysis. The resulting concentration is 5 g/l KOH. Store this
solution at room temperature. Reagent expires 6 months after preparation date.
3.10.7 Carrier solution
This solution is equivalent to the wash solution (3.10.4). The carrier solution is used to deliver the sample
solution to the nebulizer through the ICP-MS autosampler introduction system. The carrier solution is
introduced via a peristaltic pump using 0,76 mm inside diameter (id) two-stop polyvinyl chloride pump
tubing. Store this solution at room temperature. Reagent expires 6 months after preparation date.
3.11 Preparation of standard solutions
3.11.1 General
Stock solutions are stable until the end date indicated on the certificate of analysis. Intermediate stock
standard, calibration standard, continuing calibration verification and internal standard solutions
are stable at room temperature until the earliest expiration date of all components used to prepare
the solution. These solutions are ready to use for analysis. Do not subject them to any of the various
procedures used to prepare actual samples (i.e. infant formulas and adult nutritionals) for analysis.
3.11.2 Stock iodine and praseodymium solutions
Purchase of stock iodine and praseodymium standard solutions with accompanying certificates of
analysis is recommended.
3.11.3 Intermediate stock standard (ISS) iodine solutions
Prepare the intermediate stock standard iodine solutions according to Table 1.
These ISS solutions are used for calibration standard preparation and are typically prepared according
to Table 1. The ISS concentrations presented are nominal. Using the stock iodine concentration found
on the certificate of analysis, determine the exact concentration of each ISS. An electronic adjustable
volume pipet, capable of delivering 100 µl to 5 000 µl should be used.
Table 1 — Preparation of intermediate stock standard (ISS) iodine solutions
Iodine standard ID of solution used for Initial iodine Aliquot volume Final Final iodine
solution ID preparation concentration ml volume concentration
ng/ml ml ng/ml
10 000 (ISS) Stock 1 000 000 0,5 50 10 000
1 000 (ISS) 10 000 (ISS) 10 000 5 50 1 000
10,0 (ISS) 1 000 (ISS) 1 000 0,5 50 10,0
Aliquot the appropriate amount of iodine standard solution into a single use 50 ml tube (4.1) and add 5 ml of stabilizer
concentrate (3.10.3), fill to the 50 ml mark on the tube with water, cap the tube and then mix thoroughly. The resulting
matrix concentration is 1 % NH OH and 0,1 % Na S O in water.
4 2 2 3
3.11.4 Calibration standard (CS) iodine solutions
Prepare the intermediate stock standard iodine solutions according to Table 2.
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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Typical CS standard concentrations are nominally 0,250 ng/ml, 0,500 ng/ml, 1,00 ng/ml, 10,0 ng/ml,
50,0 ng/ml and 100 ng/ml iodine and are typically prepared according to Table 2. The calibration
2)
2)
blank is the zero point of the curve. The curve type used, if using a Perkin Elmer ICP-MS with ELAN
2) 2)
software, should be linear through zero. If using an Agilent or Thermo ICP-MS, force the curve
through the calibration blank. The calibration curve shall have a correlation coefficient (r) of ≥ 0,998
to be acceptable. Determine the exact concentration of each CS (traceable back to the certificate of
analysis) and assign these values to the curve points used to generate the final results. An electronic
adjustable volume pipet, capable of delivering 100 µl to 5 000 µl should be used.
Table 2 — Preparation of calibration standard (CS) iodine and calibration blank (CB) solutions
Iodine standard ID of solution used for Initial iodine Aliquot volume Final Final iodine
solution ID preparation concentration ml volume concentration
ng/ml ml ng/ml
100 (CS) 1 000 (ISS) 1 000 5 50 100
50,0 (CS) 1 000 (ISS) 1 000 2,5 50 50,0
10,0 (CS) 1 000 (ISS) 1 000 0,5 50 10,0
1,00 (CS) 10,0 (ISS) 10,0 5 50 1,00
0,500 (CS) 10,0 (ISS) 10,0 2,5 50 0,500
0,250 (CS) 10,0 (ISS) 10,0 1,25 50 0,250
a a a
Blank (CB) n.a. n.a. n.a. 50 0
Aliquot the appropriate amount of iodine standard solution into a single use 50 ml tube (4.1) and add 5 ml of 5 % KOH and
1 ml of stabilizer concentrate (3.10.3), fill to the 50 ml mark on the tube with water, cap the tube and then mix thoroughly.
The resulting matrix concentration is 0,5 % KOH and approximately 0,2 % NH OH and approximately 0,02 % Na S O in
4 2 2 3
water.
a
n.a. is not applicable
3.11.5 Intermediate continuing calibration verification (ICCV), continuing calibration verification
(CCV) iodine solutions and continuing calibration blank (CCB) solution
A CCV solution shall be prepared from a source other than that used for the CS solutions. For example,
2
if a stock solution from SPEX CertiPrep was used to prepare the CS solutions, do not use this same
2
solution to prepare the CCV solution. Instead use a stock solution from Inorganic Ventures (or another
suitable manufacturer) to prepare the CCV solution.
Prepare the intermediate continuing calibration verification, continuing calibration verification
standards solutions and continuing calibration blank according to Table 3.
ICCV solutions are used for preparation of the CCV standard solution and are typically prepared
according to Table 3. The ICCV and CCV concentrations presented are nominal. Using the stock iodine
concentration found on the certificate of analysis (from the second source), determine the exact
concentration of each ICCV. With this information, determine the exact concentration of the CCV
standard. An electronic adjustable volume pipet, capable of delivering 100 µl to 5 000 µl should be used.

2) This is an example of a suitable product available commercially. This information is given for the convenience
of users of this document and does not constitute an endorsement by either ISO or IDF of the product named.
Equivalent products may be used if they can be shown to lead to the same results.
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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
Table 3 — Preparation of intermediate continuing calibration verification (ICCV), continuing
calibration verification (CCV) iodine solutions and continuing calibration blank (CCB) solution
Iodine standard ID of solution used for Initial iodine Aliquot volume Final Final iodine
solution ID preparation concentration ml volume concentration
ng/ml ml ng/ml
10 000 (ICCV) Stock 1 000 000 0,5 50 10 000
1 000 (ICCV) 10 000 (ICCV) 10 000 5 50 1 000
10,0 (CCV) 1 000 (ICCV) 1 000 0,5 50 10,0
a a a
Blank (CCB) n.a. n.a. n.a. 50 0
Aliquot the appropriate amount of iodine standard solution into a single use 50 ml tube (4.1), fill to the 50 ml mark on
the tube with diluent (3.10.5), cap the tube and then mix thoroughly. The resulting matrix concentration is 0,5 % KOH,
approximately 0,2 % NH OH and approximately 0,02 % Na S O in water.
4 2 2 3
For the blank (CCB), fill a single use 50 ml tube (4.1) to the 50 ml mark on the tube with diluent (3.10.5), cap the tube and
then mix thoroughly.
a
n.a. is not applicable
3.11.6 Internal standard (IS) solution
Prepare the internal standard solutions according to Table 4.
The IS concentration typically used for analysis is 30 ng/ml Pr. Table 4 outlines a typical preparation
scheme for the internal standard concentration.
Table 4 — Preparation of internal standard (IS) solution
Standard solution ID of solution used for Initial Aliquot volume Final Final iodine
ID preparation concentration ml volume concentration
ng/ml ml ng/ml
a
30,0 (Pr) Stock 10 000 1,5 500 30,0
a
After aliquoting the 10000 ng/ml Pr solution into the 500 ml vessel, add approximately 100 ml of water, 10 ml of
®
HNO , 0,5 ml of HClO , 0,05 g of Triton X-100 and then bring to volume with water and mix thoroughly. The resulting
3 4
®
concentration is 2 % HNO , 0,1 % HClO and 0,01 % Triton X-100 in water.
3 4
NOTE As some ICP-MS instruments provide greater sensitivity, the concentration of Pr may be adjusted
accordingly to provide intensities similar to the intensity generated by the 50,0 ng/ml iodine standard.
4 Apparatus
Usual laboratory glassware and equipment and, in particular, the following.
Equivalent apparatus may be used. All laboratory plasticware should be single-use whenever possible.
If reuse is necessary, wash using 10 % nitric acid, then rinse thoroughly with purified water prior to
use. When needed, general laboratory acid-washed glassware may also be used.
Filter membranes < 1 µm (e.g. 0,25 µm or 0,45 µm) may be used. Adherence as close as possible to
the recommended inside diameters of the pump tubing is critical. The ratio of the pump tubing inside
diameter (id) (0,76 mm) used for the carrier solution (see 3.10.7) to the pump tubing id (0,38 mm)
used for the internal standard solution (see 3.11.6) may be used as a guideline (0,76/0,38 = 2). For best
performance, the ratio should remain as close to 2 as possible. Vast differences in id between the carrier
solution pump tubing and the internal standard solution pump tubing (e.g. 1,02/0,19, respectively) may
result in poor accuracy.
4.1 Polypropylene tubes, capacity 50 ml and 100 ml.
4.2 Oven, e.g. warming or drying oven, set to maintain 105 °C ± 5 °C.
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oSIST prEN ISO 20647:2020
ISO 20647:2015(E)
IDF 234:2015(E)
4.3 Open-vessel microwave digestion unit, optional.
4.4 Analytical balance, capable of weighing to 0,0001 g.
4.5 Top-loader balance, capable of weighing to 0,01 g.
3)
4.6 ICP-MS system, ELAN DRC II Perkin Elmer, or equivalent.
3)
4.7 Autosampler for ICP-MS, SC4-DX , Elemental Scientific, or equivalent.
4.8 Adjustable volumetric pipets, electronic or manual, capacity 100 µl to 5 000 µl.
4.9 Re-pipet volumetric dispensers, of adjustable volume.
4.10 Polypropylene or polytetrafluoroethylene (PTFE) bottles, for storage of reagents.
4.11 Disposable plastic syringes, e.g. capacity 10 ml, with Luer Lok connections.
3)
4.12 Syringe filters, with 1 µm membrane, e.g. GMF-150 or PTFE.
4.13 Beakers, of assorted sizes.
4.14 Stir bars, 7,9 mm x 50 mm, or appropriate size.
4.15 Stir plate, adjustable speed.
4.16 Pump tubing, peristaltic, 0,76 mm inside diameter (id), two-stop polyvinyl chloride (PVC), used
for introducing carrier solution (see 3.10.7).
4.17 Pump tubing, peristaltic, 0,38 mm id, two-stop PVC, used for introducing internal standard
solution (see 3.11.6).
5 Procedure
5.1 Reconstitution
All powdered samples, with the exception of NIST SRM 1849a, are required to be analysed on a
reconstituted basis. Do not reconstitute ready-to-feed (RTF) samples.
Accurately weigh 25 g ± 0,01 g of powdered test sample into an appropriate vessel (e.g. 400 ml
beaker) and recor
...

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