1、BSI Standards PublicationBS ISO 20752:2014Cork stoppers Determinationof releasable 2, 4, 6-trichloroanisol (TCA)BS ISO 20752:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 20752:2014. It supersedes BS ISO 20752:2007 which is withdrawn.The UK participation
2、 in its preparation was entrusted to Technical Committee PRI/81, Cork.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct appli
3、cation. The British Standards Institution 2014.Published by BSI Standards Limited 2014ISBN 978 0 580 81959 9ICS 79.100Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committe
4、e on 30 June 2014.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 20752:2014 ISO 2014Cork stoppers Determination of releasable 2, 4, 6-trichloroanisol (TCA)Bouchons en lige Dosage du 2, 4, 6-trichloroanisol (TCA) relargableINTERNATIONAL STANDARDISO20752Second edition
5、2014-06-15Reference numberISO 20752:2014(E)BS ISO 20752:2014ISO 20752:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electroni
6、c 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 ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22
7、 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 20752:2014ISO 20752:2014(E) ISO 2014 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols and abbreviated terms . 15 Pri
8、nciple 16 Reagents 27 Apparatus . 28 Sampling 29 Procedure. 39.1 Calibration 39.2 Sample preparation 39.3 SPME 39.4 GC 49.5 Detection 49.6 Blank test . 410 Expression of results 411 Test report . 5Bibliography 6BS ISO 20752:2014ISO 20752:2014(E)ForewordISO (the International Organization for Standar
9、dization) 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
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14、e meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/T
15、C 87, Cork.This second edition cancels and replaces the first edition (ISO 20752:2007), which has been technically revised.iv ISO 2014 All rights reservedBS ISO 20752:2014ISO 20752:2014(E)IntroductionThis International Standard intends to simulate migration phenomena that might occur when cork stopp
16、ers are used to close wine bottles.It consists of determining the content of releasable 2,4,6-trichloroanisol (TCA) based on an equilibrium between the solid (cork) and the liquid (hydro-alcoholic simulant) matrices after submitting a sample of cork stoppers or cork constituents of cork stoppers to
17、a period of maceration in a hydro-alcoholic solution. ISO 2014 All rights reserved vBS ISO 20752:2014BS ISO 20752:2014Cork stoppers Determination of releasable 2, 4, 6-trichloroanisol (TCA)1 ScopeThis International Standard specifies a test method to determine releasable 2,4,6-trichloroanisol (TCA)
18、from cork stoppers.This International Standard is applicable to all types of cork stoppers and all their cork constituents.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references,
19、only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 633, Cork VocabularyISO 17727, Cork Cork stoppers for still wine Sampling plan for the quality control of cork stoppers3 Terms and definitionsFor the purposes
20、of this document, the terms and definitions given in ISO 633 and the following apply.3.1simulantsolution that intends to simulate the wine3.2internal standardcompound of known concentration added to a sample to facilitate the qualitative identification and/or quantitative determination of the sample
21、 components4 Symbols and abbreviated termsPDMS polydimethylsiloxaneGC/ECD gas chromatography/electron capture detectorGC-MS gas chromatography/mass spectrometrySPME solid phase microextractionTCA 2,4,6-trichloroanisol5 PrincipleDetermination of releasable TCA from cork stoppers, previously subjected
22、 to maceration in a wine simulant, using solid-phase microextraction followed by the detection and quantification of this compound by GC-MS or GC/ECD.INTERNATIONAL STANDARD ISO 20752:2014(E) ISO 2014 All rights reserved 1BS ISO 20752:2014ISO 20752:2014(E)6 ReagentsUse only reagents of recognized ana
23、lytical grade.6.1 Hydro-alcoholic solution, 12 % (v/v) (wine simulant).6.2 Ethanol, with a minimum purity of 95 %.6.3 Distilled water.6.4 Sodium chloride (NaCl) p.a.6.5 Internal standard, (GC-MS) 2,4,6-trichloroanisol (TCA) d5, purity 98 % or (GC/ECD) 2,3,6trichloroanisol, purity 99 %.6.6 2,4,6-tric
24、hloroanisol (TCA), purity 99 %.7 ApparatusThe usual laboratory apparatus and, in particular, the following:7.1 Balance, with a resolution of, at least, 0,1 mg.7.2 Glass maceration flasks, with a stopper made of glass, metal, or any other material not absorbing TCA and an appropriate capacity to the
25、sample size.7.3 Glass flasks (vial), with 10 ml minimum capacity (solution shall occupy at least 50 % of the vial capacity) with a septum and an appropriate stopper.7.4 SPME fibre.EXAMPLE 100 m PDMS.7.5 Heating source, for the vial (7.3), set between 30 C and 50 C.7.6 Automatic stirring system, for
26、the SPME.7.7 Appropriate gas, of chromatographic purity.7.8 Gas chromatograph, with a mass detector, MS, or an electron capture detector, ECD.7.9 Low-polarity fused silica capillary column.EXAMPLE Length of 30 m, internal diameter of 0,25 mm, film thickness of 0,25 m; stationary phase: copolymer of
27、5 % diphenyl and 95 % dimethyl polysiloxane.8 SamplingThe size of the sample to be tested shall be in accordance with the sampling standard (ISO 17727) or agreed between customer and supplier.2 ISO 2014 All rights reservedBS ISO 20752:2014ISO 20752:2014(E)9 Procedure9.1 CalibrationThe set of calibra
28、tion solutions for TCA is obtained by adding known concentrations of analyte to the wine simulant. Standard solutions from 0,5 ng/L to 10 ng/L can be used.The calibration curve obtained shall be evaluated regularly and whenever any large change is recorded by the GC-MS or GC/ECD.9.2 Sample preparati
29、onIntact straight cork stoppers are subjected to maceration for 24 h 2 h at room temperature, using enough wine simulant, to keep the stoppers entirely immersed, and then analyse the macerate.EXAMPLE 1 20 corks (45 24) mm, in a 1 L flask.EXAMPLE 2 50 stoppers (45 24) mm, in a 2 L flask.For bar-top s
30、toppers, cut off the flange before maceration.For granulated cork, 40 g of granulated cork are subjected to maceration for 24 h 2 h at room temperature in a 2 L flask, using enough wine simulant to keep the granulated cork entirely immersed, and then analyse the macerate.For cork discs, 20 cork disc
31、s are subjected to maceration for 24 h 2 h at room temperature in a 0,5 L flask, using enough wine simulant to keep the granulated cork entirely immersed, and then analyse the macerate.For cork stoppers for sparkling wines, immerse in the wine simulant only the discs of natural cork and 1 cm of the
32、agglomerate without cutting the stoppers, for 24 h 2 h at room temperature, and then analyse the macerate.9.3 SPME9.3.1 Test portionTake a volume of the solution to be tested not greater than 50 % of the vial capacity (7.3).EXAMPLE 1 For a vial (7.3) of 20 mL, take 10 mL, in such a way that the fibr
33、e does not touch the liquid.The test portion should be saturated with NaCl (approximately 0,30 g/mL).Add the internal standard solution, 12 %, v/v ethanol/water, to the test portion in the vial (7.3) in such a way that the ethanol content and the total volume of the liquid do not change significantl
34、y.EXAMPLE 2 100 L internal standard solution/10 mL total liquid.The concentration of the internal standard solution shall be in the calibration curve range and shall be as close as possible to the specification.9.3.2 AdsorptionAdjust the time and temperature in the headspace, according to the fibre
35、used.EXAMPLE Fibre PDMS 100 m, 15 min in the headspace, stirring at a temperature of 35 C 2 C. ISO 2014 All rights reserved 3BS ISO 20752:2014ISO 20752:2014(E)9.4 GC9.4.1 DesorptionSplitless injection from 1 min to 2 min at 250 C. The fibre shall be conditioned/cleaned between two extractions.9.4.2
36、Chromatographic analysisThe resolution grade and the time needed for the chromatographic separation shall be optimized by using a temperature program.An example of a temperature program is shown below.Temperature Time Increment50 C 2 min From 50 C to 150 C 9 C/min150 C 0,5 min From 150 C to 260 C 20
37、 C/min260 C 5 min 9.5 Detection9.5.1 Determination by MSDetection either in SIM or in MS/MS mode with detection of 3 ions, and quantification through the most abundant ion.Ions are the following: for 2,4,6 TCA: m/z 195, 210, 212, quantification with m/z 195; for 2,4,6 TCA d5: m/z 199, 215, 217, quan
38、tification with m/z 215.The operating conditions in MS/MS mode are shown in Table 1.Table 1 Operating conditions in MS/MS modeCompound Precursor ion Product ion2,4,6 TCA d5217 199 1712,4,6 TCA 212 197 1699.5.2 Determination by ECDIdentify the peaks corresponding to analyte and to the internal standa
39、rd by comparing, on the chromatogram, the retention time in the sample with the retention time in the standard peak.9.6 Blank testCarry out a parallel test, without the stoppers mentioned in 9.2.10 Expression of resultsThe results shall be expressed in nanogram per litre and shall be rounded to the
40、nearest to 0,5.4 ISO 2014 All rights reservedBS ISO 20752:2014ISO 20752:2014(E)11 Test reportThe test report shall include the following information:a) number of stoppers tested and capacity of the maceration flask used;b) reference to this International Standard (i.e. ISO 20752);c) all data needed
41、to identify completely the tested sample;d) capillary column used, gas chromatography conditions applied, and type of detection used;e) internal standard used;f) concentration of releasable 2,4,6 TCA, in nanogram per litre;g) detection limit and quantification limit;h) any incident likely to have af
42、fected the results, noted during the analysis;i) all optional operations or those not specified in this International Standard. ISO 2014 All rights reserved 5BS ISO 20752:2014ISO 20752:2014(E)Bibliography1 ISO 2718, Standard layout for a method of chemical analysis by gas chromatography2 ISO/IEC 170
43、43, Conformity assessment General requirements for proficiency testing3 NF V 03-110Dcembre 1998, Analyse des produits agricoles et alimentaires - Procdure de validation intralaboratoire dune mthode alternative par rapport une mthode de rfrence - Cas de mthodes danalyse quantitatives4 G-CSQ-02, Guia
44、para los laboratorios que realizan validaciones de mtodos de anlisis qumicos5 Relacre Guia 13, Fevereiro 2000, Validao de mtodos internos de ensaio em anlise qumica6 IUPAC Compendium of Chemical Terminology. Second Edition, 19976 ISO 2014 All rights reservedBS ISO 20752:2014BS ISO 20752:2014ISO 2075
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