SIST EN 62321-7-2:2017
(Main)Determination of certain substances in electrotechnical products - Part 7-2: Hexavalent chromium - Determination of hexavalent chromium (Cr(VI)) in polymers and electronics by the colorimetric method
Determination of certain substances in electrotechnical products - Part 7-2: Hexavalent chromium - Determination of hexavalent chromium (Cr(VI)) in polymers and electronics by the colorimetric method
This part of IEC 62321 describes procedures to measure hexavalent chromium, Cr(VI), quantitatively in samples of polymers and electronics. This method employs organic solvent to dissolve or swell the sample matrix, followed by an alkaline digestion procedure to extract Cr(VI) from samples. Studies have shown that organic/alkaline solution is more effective than acidic solution in extracting Cr(VI) from soluble and insoluble samples. Minimal reduction of Cr(VI) to Cr(III) or oxidation of Cr(III) to Cr(VI) occurs under alkaline conditions.
For soluble polymers consisting of ABS (Acrylonitrile- butadiene-styrene), PC (Polycarbonate) and PVC (poly(vinyl chloride)), the samples are first dissolved in an appropriate organic solvent and Cr(VI) is then extracted by an alkaline extraction solution.
For insoluble/unknown polymers, or electronic materials that do not contain antimony (Sb), the samples are digested in a toluene/alkaline solution at 150 °C to 160 °C. Then the organic phase in the extracts are separated and discarded; the inorganic phase is retained for Cr(VI) analysis.
The Cr(VI) concentration in the extract is determined by its reaction under acidic conditions with 1,5-diphenylcarbazide. Cr(VI) is reduced to Cr(III) in the reaction with diphenylcarbazide which is oxidized to diphenylcarbazone. The Cr(III) and diphenylcarbazone form a red-violetcoloured complex in the reaction. The complex solution is measured quantitatively by a colorimeter or a spectrophotometer at 540 nm.
Verfahren zur Bestimmung von bestimmten Substanzen in Produkten der Elektrotechnik - Teil 7-2: Sechswertiges Chrom - Bestimmung von sechswertigem Chrom (Cr(VI)) in Polymeren und Elektronik durch das kolorimetrische Verfahren
Détermination de certaines substances dans les produits électrotechniques - Partie 7-2: Chrome hexavalent - Détermination du chrome hexavalent (Cr(VI)) dans les polymères et les produits électroniques par méthode colorimétrique
l'IEC 62321-7-2:2017 décrit des procédures de mesure quantitative du chrome hexavalent, Cr(VI), dans des échantillons de polymères et de produits électroniques. Cette méthode emploie un solvant organique destiné à dissoudre ou à faire gonfler la matrice de l'échantillon, puis une procédure de digestion alcaline visant à extraire le chrome hexavalent des échantillons. Des études ont démontré que la solution alcaline/organique est plus efficace que la solution acide pour extraire le Cr(VI) d'échantillons solubles et insolubles. La réduction minimale du Cr(VI) en Cr(III) ou l'oxydation du Cr(III) en Cr(VI) se produit en milieu alcalin.
La première édition de l'IEC 62321:2008 était une norme "autonome" qui comprenait une introduction, une vue d'ensemble des méthodes d'essai, la préparation mécanique d'échantillon, ainsi que différents articles relatifs à des méthodes d'essai. Cette première édition de l'IEC 62321-7-2 remplace en partie l'IEC 62321:2008, constituant une révision structurelle et remplaçant, en général, l'Annexe C. L'IEC 62321-7-2 remplace définitivement les articles correspondants dans l'IEC 62321:2008.
Določevanje posameznih substanc v elektrotehniških izdelkih - 7-2. del: Šestvalentni krom - Določevanje šestvalentnega kroma (Cr(VI)) v polimerih in elektroniki s kolorimetrično metodo
Ta del IEC 62321 opisuje postopke za količinsko merjenje šestvalentnega kroma (Cr(VI)) v vzorcih polimerov in elektronike. Metoda določa uporabo organskega topila, s katerim se matrica vzorca raztopi ali nabrekne, temu pa sledi postopek alkalnega razklopa za izločanje Cr(VI) iz vzorcev. Študije so pokazale, da je organska/alkalna raztopina učinkovitejša od kisle raztopine pri izločanju Cr(VI) iz topnih in netopnih vzorcev. Minimalna redukcija Cr(VI) v Cr(III) ali oksidacija Cr(III) v Cr(VI) se pojavi pri alkalnih pogojih.
Pri topnih polimerih, sestavljenih iz akrilonitril-butadienstirena (ABS), polikarbonata (PC) in polivinilklorida (PVC), je treba vzorce najprej raztopiti v ustreznem organskem topilu in nato izločiti Cr(VI) z alkalno raztopino za izločanje.
Pri netopnih/neznanih polimerih ali elektronskih materialih, ki ne vsebujejo antimona (Sb), je treba vzorce obdelati v raztopini toluena/alkalni raztopini pri 150–160 °C. Nato je treba ločiti in zavreči organsko fazo v ekstraktih, anorgansko fazo pa ohraniti za analizo Cr(VI).
Koncentracija Cr(VI) v ekstraktu se določi glede na njeno reakcijo v kislih pogojih z 1,5-difenilkarbazidom. Cr(VI) je reduciran v Cr(III) v reakciji z difenilkarbazidom, ki oksidira v difenilkarbazon. Cr(III) in difenilkarbazon v reakciji tvorita rdečevijolični sestav. Raztopina se meri kvantitativno s kolorimetrom ali spektrofotometrom pri 540 nm.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Determination of certain substances in electrotechnical products - Part 7-2: Hexavalent chromium - Determination of hexavalent chromium (Cr(VI)) in polymers and electronics by the colorimetric method71.040.50Fizikalnokemijske analitske metodePhysicochemical methods of analysis31.020Elektronske komponente na splošnoElectronic components in general29.020Elektrotehnika na splošnoElectrical engineering in generalICS:Ta slovenski standard je istoveten z:EN 62321-7-2:2017SIST EN 62321-7-2:2017en01-september-2017SIST EN 62321-7-2:2017SLOVENSKI
STANDARDSIST EN 62321:20091DGRPHãþD
SIST EN 62321-7-2:2017
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 62321-7-2
June 2017 ICS 31.020; 71.040.50
Supersedes
EN 62321:2009 (partially)
English Version
Determination of certain substances in electrotechnical products - Part 7-2: Hexavalent chromium - Determination of hexavalent chromium (Cr(VI)) in polymers and electronics by the colorimetric method (IEC 62321-7-2:2017)
Détermination de certaines substances dans les produits électrotechniques - Partie 7-2: Chrome hexavalent - Détermination du chrome hexavalent (Cr(VI)) dans les polymères et les produits électroniques par méthode colorimétrique (IEC 62321-7-2:2017)
Verfahren zur Bestimmung von bestimmten Substanzen in Produkten der Elektrotechnik - Teil 7-2: Bestimmung von sechswertigem Chrom (Cr(VI)) in Polymeren und Elektronik durch kolorimetrische Verfahren (IEC 62321-7-2:2017) This European Standard was approved by CENELEC on 2017-05-02. CENELEC 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 CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17,
B-1000 Brussels © 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 62321-7-2:2017 E SIST EN 62321-7-2:2017
EN 62321-7-2:2017 2 European foreword The text of document 111/408/CDV, future edition 1 of IEC 62321-7-2, prepared by IEC/TC 111 "Environmental standardization for electrical and electronic products and systems" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 62321-7-2:2017.
The following dates are fixed: • latest date by which the document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2018-02-02 • latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2020-05-02
This document supersedes EN 62321:2009 (partially).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 62321-7-2.2017 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 62321:2008 NOTE Harmonized as EN 62321:2009. IEC 62321-2 NOTE Harmonized as EN 62321-2. ISO 648 NOTE Harmonized as EN ISO 648.
SIST EN 62321-7-2:2017
EN 62321-7-2:2017 3
Annex ZA (normative)
Normative references to international publications with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here: www.cenelec.eu.
Publication Year Title EN/HD Year IEC 62321-1 -
Determination of certain substances in electrotechnical products -- Part 1: Introduction and overview EN 62321-1 -
ISO 3696 -
Water for analytical laboratory use - Specification and test methods EN ISO 3696 -
SIST EN 62321-7-2:2017
SIST EN 62321-7-2:2017
IEC 62321-7-2 Edition 1.0 2017-03 INTERNATIONAL STANDARD NORME INTERNATIONALE Determination of certain substances in electrotechnical products –
Part 7-2: Hexavalent chromium – Determination of hexavalent chromium (Cr(VI)) in polymers and electronics by the colorimetric method
Détermination de certaines substances dans les produits électrotechniques –
Partie 7-2: Chrome hexavalent – Détermination du chrome hexavalent (Cr(VI)) dans les polymères et les produits électroniques par méthode colorimétrique
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE
ICS 31.020; 71.040.50
ISBN 978-2-8322-4085-4
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale ®
Warning! Make sure that you obtained this publication from an authorized distributor.
Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé. SIST EN 62321-7-2:2017
– 2 – IEC 62321-7-2:2017 IEC 2017
CONTENTS FOREWORD . 3 INTRODUCTION . 5 1 Scope . 6 2 Normative references . 6 3 Terms, definitions and abbreviated terms . 6 3.1 Terms and definitions . 6 3.2 Abbreviated terms . 7 4 Reagents . 7 4.1 General . 7 4.2 Reagents . 7 5 Apparatus . 8 5.1 General . 8 5.2 Apparatus . 8 6 Sampling . 9 7 Test procedure . 9 7.1 Extraction of Cr(VI) in soluble polymers – ABS, PC and PVC matrixes . 9 7.2 Extraction of Cr(VI) in insoluble/unknown polymers and electronics − without Sb . 10 8 Calibration . 11 8.1 Permanent calibration instruments . 11 8.2 Traditional calibration instruments . 11 8.2.1 General . 11 9 Calculation . 12 10 Precision . 13 11 Quality assurance and control . 14 11.1 General method . 14 11.2 Matrix spike recovery correction method . 14 12 Limits of detection (LOD) and limits of quantification (LOQ) . 14 12.1 General . 14 12.2 Determination of LOD and LOQ . 15 13 Test report . 16 Bibliography . 17
Table 1 – Statistical data of all IIS trails . 13 Table 2 – Method detection limit = t=×=sn–1 . 16
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IEC 62321-7-2:2017 IEC 2017 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
DETERMINATION OF CERTAIN SUBSTANCES
IN ELECTROTECHNICAL PRODUCTS –
Part 7-2: Hexavalent chromium – Determination of hexavalent chromium (Cr(VI)) in polymers and electronics by the colorimetric method
FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 62321-7-2 has been prepared by IEC technical committee 111: Environmental standardization for electrical and electronic products and systems. The first edition of IEC 62321:2008 was a ‘stand-alone’ standard that included an introduction, an overview of test methods, a mechanical sample preparation as well as various test method clauses. This first edition of IEC 62321-7-2 is a partial replacement of IEC 62321:2008, forming a structural revision and generally replacing Annex C. IEC 62321-7-2 is the final replacement part of the corresponding clauses in IEC 62321:2008. SIST EN 62321-7-2:2017
– 4 – IEC 62321-7-2:2017 IEC 2017 The text of this standard is based on the following documents: CDV Report on voting 111/408/CDV 111/432/RVC
Full information on the voting for the approval of this International Standard can be found in the report on voting indicated in the above table. This document has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts in the IEC 62321 series, published under the general title Determination of certain substances in electrotechnical products, can be found on the IEC website. The committee has decided that the contents of this document will remain unchanged until the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to the specific document. At this date, the document will be
• reconfirmed, • withdrawn, • replaced by a revised edition, or • amended.
SIST EN 62321-7-2:2017
IEC 62321-7-2:2017 IEC 2017 – 5 –
INTRODUCTION The widespread use of electrotechnical products has drawn increased attention to their impact on the environment. In many countries all over the world this has resulted in the adaptation of regulations affecting wastes, substances and energy use of electrotechnical products. The use of hexavalent chromium in electrotechnical products is of concern in many regions of the world. The purpose of this document is therefore to provide test methods that will allow the electrotechnical industry to determine the levels of hexavalent chromium in electrotechnical products on a consistent global basis. 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 and to ensure compliance with any national regulatory conditions.
SIST EN 62321-7-2:2017
– 6 – IEC 62321-7-2:2017 IEC 2017 DETERMINATION OF CERTAIN SUBSTANCES
IN ELECTROTECHNICAL PRODUCTS –
Part 7-2: Hexavalent chromium – Determination of hexavalent chromium (Cr(VI)) in polymers and electronics by the colorimetric method
1 Scope This part of IEC 62321 describes procedures to measure hexavalent chromium, Cr(VI), quantitatively in samples of polymers and electronics. This method employs organic solvent to dissolve or swell the sample matrix, followed by an alkaline digestion procedure to extract Cr(VI) from samples. Studies have shown that organic/alkaline solution is more effective than acidic solution in extracting Cr(VI) from soluble and insoluble samples. Minimal reduction of Cr(VI) to Cr(III) or oxidation of Cr(III) to Cr(VI) occurs under alkaline conditions. For soluble polymers consisting of ABS (Acrylonitrile- butadiene-styrene), PC (Polycarbonate) and PVC (poly(vinyl chloride)), the samples are first dissolved in an appropriate organic solvent and Cr(VI) is then extracted by an alkaline extraction solution. For insoluble/unknown polymers, or electronic materials that do not contain antimony (Sb), the samples are digested in a toluene/alkaline solution at 150 °C to 160 °C. Then the organic phase in the extracts are separated and discarded; the inorganic phase is retained for Cr(VI) analysis. The Cr(VI) concentration in the extract is determined by its reaction under acidic conditions with 1,5-diphenylcarbazide. Cr(VI) is reduced to Cr(III) in the reaction with diphenylcarbazide which is oxidized to diphenylcarbazone. The Cr(III) and diphenylcarbazone form a red-violet-coloured complex in the reaction. The complex solution is measured quantitatively by a colorimeter or a spectrophotometer at 540 nm. 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. IEC 62321-1, Determination of certain substances in electrotechnical products – Part 1: Introduction and overview ISO 3696, Water for analytical laboratory use – Specification and test methods 3 Terms, definitions and abbreviated terms 3.1 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 62321-1 apply. SIST EN 62321-7-2:2017
IEC 62321-7-2:2017 IEC 2017 – 7 –
ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.2 Abbreviated terms For the purposes of this document, the abbreviated terms given in IEC 62321-1 apply. 4 Reagents 4.1 General Use only reagents of recognized analytical grade, unless otherwise specified. 4.2 Reagents The following reagents shall be used: a) N-Methyl-pyrrolidone (NMP), analytical reagent grade. Add 10 g activated molecular sieves (4.2 r)) per 100 ml of newly opened NMP, seal the cap tightly, keep in the dark, shake occasionally and maintain over 12 h before first use. Store at 20 °C to 25 °C with molecular sieves in a tightly sealed brown glass container and avoid direct light exposure. The suggested maximum storage period is four weeks after the opening time of the container. b) Nitric acid, volume fraction of 35 %. Dilute 50 ml of reagent grade HNO3 to 100 ml with water (see 4.2 p)) in a volumetric flask (5.2 j)). Store at 20 °C to 25 °C in the dark. Do not use concentrated HNO3 if it has a yellow colour, which is an indication of photoreduction of NO3- to NO2-, a reducing agent for Cr(VI). c) Sodium carbonate: Na2CO3, anhydrous, analytical reagent grade. d) Sodium hydroxide: NaOH, analytical reagent grade. e) Magnesium chloride: MgCl2 (anhydrous), analytical reagent grade. A mass of 200 mg MgCl2 is approximately equivalent to 50 mg Mg2+. f) Phosphate buffer. To prepare a buffer solution at pH 7, dissolve 87,09 g K2HPO4 (analytical reagent grade) and 68,04 g KH2PO4 (analytical reagent grade) into 700 ml of water (4.2 p)). Transfer to a 1 l volumetric flask (5.2 j)) and dilute to volume. As prepared, the solution will contain 0,5 mol/l K2HPO4 and 0,5 mol/l KH2PO4. g) Lead chromate: PbCrO4, analytical reagent grade. Store at 20 °C to 25 °C in a tightly sealed container. This is the agent used for the matrix spike recovery correction method. h) Digestion solution. Dissolve 20,0 g ± 0,05 g NaOH and 30,0 g ± 0,05 g Na2CO3 in water (4.2 p)) in a 1 l volumetric flask (5.2 j)) and dilute to the mark. Store the solution in a tightly capped polyethylene bottle at 20 °C to 25 °C, and prepare fresh monthly. The pH of the digestion solution shall be checked before using. If the pH is <=11,5 discard the solution and prepare a fresh batch. i) Toluene, analytical reagent grade. j) Potassium dichromate stock solution. Dissolve 141,4 mg of dried (105 °C) K2Cr2O7 (analytical reagent grade) in water (4.2 p)) and dilute to 1 l in a volumetric flask (5.2 j)) (1 ml contains 50 µg Cr). k) Potassium dichromate standard solution. Dilute 10 ml potassium dichromate stock solution (4.2 j)) with water (4.2 p)) to 100 ml in a volumetric flask (5.2 j)) (1 ml contains 5 µg Cr). l) Sulfuric acid, volume fraction of 10 %. Dilute 10 ml of distilled reagent grade or spectroscopic grade H2SO4 to 100 ml with water (4.2 p)) in a volumetric flask (5.2 j)). m) Diphenylcarbazide solution. Dissolve 250 mg 1,5-diphenylcarbazide in 50 ml acetone (4.2 q)). Store in a brown bottle. Prior to use, check the solution for discoloration. Store for SIST EN 62321-7-2:2017
– 8 – IEC 62321-7-2:2017 IEC 2017 use up to two weeks and if solution becomes discoloured, discard it and prepare a fresh batch. n) Potassium dichromate, K2Cr2O7, spike solution 1 000 mg/l Cr(VI)). Dissolve 2,829 g of dried (105 °C) K2Cr2O7 in water (4.2 p)) in a 1 l volumetric flask (5.2 j)), and dilute to the mark. Alternatively, a 1 000 mg/l Cr(VI)-certified standard solution can be used. Store for use up to six months at 20 °C to 25 °C in a tightly sealed container. o) Potassium dichromate, K2Cr2O7, matrix spike solution (100 mg/l Cr(VI)): Add 10,0 ml of the 1 000 mg/l Cr(VI) solution made from K2Cr2O7 spike solution (4.2 n)) to a 100 ml volumetric flask (5.2 j)) and dilute to volume with water (4.2. p)). Mix well. p) Water. Grade 3 specified in ISO 3696, which shall be free of interferences. q) Acetone, analytical reagent grade. r) Molecular sieves (4A), CAS: 70955-01-0, desiccant. WARNING – All potential Cr(VI)-containing samples and reagents used in the method have to be handled with appropriate precautions. Solutions or waste material containing Cr(VI) have to be disposed of properly. For example, ascorbic acid or some other reducing agents can be used to reduce Cr(VI) to Cr(III). 5 Apparatus 5.1 General All re-usable laboratory ware (glass, quartz, polyethylene, polytetrafluoroethylene (PTFE), etc.) including the sample containers shall be soaked overnight in laboratory-grade detergent and water, rinsed with water, and soaked for 4 h or more in HNO3 (volume fraction of 20 %) or in a mixture of dilute acids (HNO3:HCl:H2O = 1:2:9 by volume) followed by rinsing with water (4.2 p)). Alternative cleaning procedures are permitted, provided adequate cleanliness can be demonstrated through the analysis of method blanks. 5.2 Apparatus The following items shall be used for the analysis: a) Vacuum filtration apparatus. b) Heating or microwave device capable of maintaining the digestion solution at temperatures between 150 °C and 160 °C. c) Ultrasonic water bath, capable of maintaining the temperature between 60 °C and 65 °C. d) Calibrated pH meter to read pH in a range of 0 to 14 with an accuracy of ±0,03 pH units. e) Analytical balance capable of measurement to 0,1 mg. f) Thermometer, thermistor or other temperature measurement device capable of measuring up to 160 °C. g) Colorimetric instrument: either a spectrophotometer for use at 540 nm, providing a light path of 1 cm or longer or a filter photometer, providing a light path of 1 cm or longer and equipped with a filter having maximum transmittance near 540 nm. h) Grinding mill, with or without liquid nitrogen cooling, capable of grinding polymer samples and electronic components. i) Borosilicate glass or quartz beaker with volume graduation of 150 ml, or equivalent. j) Volumetric glassware: Class A or equivalent of acceptable precision and accuracy. Alternative volumetric equipment (e.g. automatic dilutors) with equivalent precision and accuracy can be used. k) Assorted calibrated pipettes: Class A glassware or other with equivalent precision and accuracy. l) Digestion vessel: Glass screw thread bottle (wide neck), volume of 50 ml and minimum inner diameter of 3 cm. SIST EN 62321-7-2:2017
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m) Glass separatory funnel, 100 ml. n) Filter membranes (0,45 µm): preferably cellulose-based or PC membranes; filter syringe (0,45 µm): nylon or PVDF. o) C18 syringe filter cartridge. p) Microwave digestion vessel or a suitable borosilicate glass or quartz vessel equipped with a membrane for pressure relief over 1,0 MPa and volume graduation of 50 ml or equivalent. 6 Sampling Samples shall be collected and stored using devices and containers that do not contain stainless steel. For soluble polymers (ABS, PC and PVC), a particle size larger than 250 µm is acceptable, however, a longer dissolution time may be required to completely dissolve the polymer matrix. Insoluble or unknown polymers and electronic components that do not contain Sb shall be ground into a fine powder (5.2. h)) prior to digestion to promote extraction, with 100 % of the material passing through a 250 µm sieve, for example a No. 60 ASTM standard sieve. If the identity of the polymer matrix is unknown, a solubility test can be performed by testing a small amount of the sample using an organic solvent. Alternatively, infrared spectroscopy (IR) can be performed to identify the bulk polymer. The presence of Sb can be detected by X-ray fluorescence spectroscopy (XRF). 7 Test procedure 7.1 Extraction of Cr(VI) in soluble polymers – ABS, PC and PVC matrixes a) Accurately weigh a sample of 0,1 g. Place the sample into a digestion vessel (5.2. l)). NOTE Alternative sample amounts can be used for samples with potentially very low or very high Cr(VI) concentrations. b) Place 10 ml of NMP (4.2. a)) into the digestion vessel (5.2. l)) and seal the cap tightly. c) Dissolve each polymer sample by ultrasonication (5.2 c)) at 60 °C for 1 h. Shake the sample vessel by hand for about 10 s to suspend insoluble particles, then ultrasonicate at 60 °C for 1 h again. The sample matrix has to be completely dissolved before proceeding to the next step. d) To test for recovery in every matrix, accurately weigh a second sample of 0,1 g (or another chosen amount of sample). Place it into the digestion vessel (5.2. l)) and add 10 ml of NMP (4.2 a)) into the vessel and seal the cap tightly. Then proceed with step 7.1 c), choose a matrix spike solution (4.2 o)) and add it directly to the sample. Follow steps from
7.1 e) to 7.1 o). e) Shake the digestion vessel by hand and mix well, then add 200 mg MgCl2 (4.2 e)) and 0,5 ml of 0,5 mol/L phosphate buffer (4.2 f)) to each digestion vessel. Shake the digestion vessel again and mix well. f) Measure 20 ml of the digestion solution (4.2 h)) using a graduated cylinder (5.2 j)) and slowly pour into each digestion vessel (5.1 l)). Mix well. g) Ultrasonicate above solution at 60 °C for 1 h (shake the digestion vessel by hand and mix well after 0,5 h). h) Transfer above content to a 150 ml beaker (5.2 i)). With constant stirring while monitoring the pH, add HNO3 (4.2 b)) dropwise to the beaker. Adjust the pH of the solution to 7,5 ±=0,5. i) Even if the sample solution is turbid or flocculent precipitates are present, do not filter the sample solution. SIST EN 62321-7-2:2017
– 10 – IEC 62321-7-2:2017 IEC 2017 j) Add 2,5 ml diphenylcarbazide solution (4.2 m)) to each vessel. Slowly add H2SO4 solution (4.2 l)) to the vessel and adjust the pH of the solution to 2,0 ± 0,5. k) Transfer the contents of the vessel quantitatively to a 100 ml volumetric flask (5.2 j)) and make up to the mark by water (4.2 p)). Mix well. l) Filter the coloured sample solution using the 0,45 µm syringe filter (5.2 n)). m) Transfer an appropriate portion of the solution to a 1 cm absorption cell and measure its absorbance at 540 nm with a colorimetric instrument (5.2 g)). Measurement shall be taken within 30 min of colour development. n) Correct the absorbance reading of the sample by subtracting the absorbance of a blank carried through the colour development procedures. o) From the corrected absorbance, determine the concentration of Cr(VI) present by referring to the calibration curve. 7.2 Extraction of Cr(VI) in insoluble/unknown polymers and electronics − without Sb a) Accurately weigh a sample of 0,15 g. Place the sample into a digestion vessel (5.2 p)). NOTE Alternative sample amounts can be used for samples with potentially very low or very high Cr(VI) concentrations. b) To each
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