BS-ISO-20752-2007.pdf

BRITISH STANDARD BS ISO 20752:2007 Cork stoppers Determination of releasable 2, 4, 6-trichloroanisol (TCA) ICS 79.100 ? Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS ISO 20752:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 June 2007 © BSI 2007 ISBN 978 0 580 56172 6 National foreword This British Standard was published by BSI. It is the UK implementation of ISO 20752:2007. The UK participation 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 application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI Reference number ISO 20752:2007(E) INTERNATIONAL STANDARD ISO 20752 Cork stoppers Determination of releasable 2, 4, 6-trichloroanisol (TCA) Bouchons en liège Dosage du 2, 4, 6-trichloroanisol (TCA) relargable BS ISO 20752-2007 First edition 2007-02-01 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ii Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 1 4 Symbols and abbreviated terms . 1 5 Principle. 2 6 Reagents 2 7 Apparatus 2 8 Sampling 3 9 Procedure 3 10 Expression of results . 4 11 Test report . 5 Bibliography. 6 BS ISO 20752-2007 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. 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. ISO 20752 was prepared by Technical Committee ISO/TC 87, Cork. BS ISO 20752-2007 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI v Introduction This method intends to simulate migration phenomena that may occur when cork stoppers are used to close wine bottles. It consists of determining the releasable 2,4,6-trichloroanisol (TCA) based on an equilibrium between the solid (cork) and the liquid (hydro-alcoholic simulator) matrices, after submitting a sample of cork stoppers to a period of maceration in a hydro-alcoholic solution. BS ISO 20752-2007 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 1 Cork stoppers Determination of releasable 2, 4, 6-trichloroanisol (TCA) 1 Scope This International Standard specifies a test method to determine releasable 2,4,6-trichloroanisol (TCA) from cork stoppers. This International Standard is applicable to all types of cork stoppers. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 633 1), Cork Vocabulary 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 633, and the following, apply. 3.1 simulator solution that intends to simulate the wine 3.2 internal standard compound of known concentration added to a sample to facilitate the qualitative identification and/or quantitative determination of the sample components 4 Symbols and abbreviated terms GC/ECD GC/MS Gas chromatography/electron-capture detector Gas chromatography/mass spectrometry SPME Solid phase microextraction TCA 2,4,6-Trichloroanisol 1) Under revision. BS ISO 20752-2007 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 2 5 Principle Determination of releasable 2,4,6-trichloroanisol (TCA) from cork stoppers, previously subjected to maceration in a wine simulator, using solid-phase microextraction followed by the detection and quantification of this compound by GC/MS or GC/ECD. 6 Reagents Use only reagents of recognized analytical grade and distilled water. 6.1 Hydro-alcoholic solution, 12 % (volume fraction). 6.2 Absolute ethanol. 6.4 Sodium chloride (NaCl). 6.5 2,4,6-Trichloroanisol (TCA) d5, purity W 98 % (for GC/MS). 6.6 2,4,6-Trichloroanisol (TCA), purity W 99 %. 6.7 Selected internal standard, purity W 99 % (for GC/ECD), of 2.3.6-T.C.A, for example. 7 Apparatus Standard laboratory apparatus and the following. 7.1 Balance, with a resolution of at least 0,1 mg. 7.2 Glass maceration flasks, with a stopper of glass or metal or any other material not absorbing TCA, and with a capacity appropriate to the sample size. 7.3 Glass flasks (vial), of 10 ml minimum capacity (solution shall occupy at least 50 % of the vial capacity), with a silicone/PTFE septum and an appropriate stopper. 7.4 SPME fibre, 100 µm polydimethlysiloxane PDMS, with either a manual support or a support suitable for automatic operation. 7.5 Heating source for the vial, set at a temperature of 35 °C. 7.6 Automatic stirring system, for the SPME. 7.7 Appropriated gas, of chromatographic purity. 7.8 Gas chromatograph, with a mass detector (MS) or an electron-capture detector (ECD). 7.9 Capillary column of light polarity silica glass. EXAMPLE Operating conditions: length 30 m, inside diameter 0,25 mm, film thickness 0,25 µm, stationary phase: diphenyl copolymer (5 %) and dimethylsiloxane (95 %). BS ISO 20752-2007 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 3 8 Sampling The size of the sample to be tested will be agreed upon by the customer and supplier. 9 Procedure 9.1 Calibration Add known concentrations to the wine simulator to obtain the set of calibration solutions for TCA. Standard solutions from 0,5 ng/l to 50 ng/l can be used. Evaluate regularly the calibration curve obtained, re-evaluate it whenever any large change is recorded by the GC/MS or GC/ECD. 9.2 Sample preparation Subject straight cork stoppers, “ras-de-bague”, to maceration for 24 h ± 2 h at room temperature, using enough simulator to keep the stoppers totally immersed. For bar-top stoppers, cut off the flange before macerating. EXAMPLE 50 stoppers of 45 mm × 24 mm, in a 2 l flask. For cork stoppers for sparkling wines, immerse only the discs of natural cork and 1 cm of the agglomerate without cutting the stoppers. 9.3 SPME 9.3.1 Test portion Take a volume of the solution to be analysed not greater than 50 % of the vial capacity (7.3); for example; 10 ml of the solution to be analysed for a vial of 20 ml, in such a way that the fibre does not touch the liquid. Saturate the test portion with NaCl (approximately 0,30 g/ml) (6.3). Add the Internal standard solution, 12 % (by volume) ethanol/water (6.1), to the test portion in the vial in such a way that the ethanol content and the total volume of the liquid do not change significantly. EXAMPLE Add 100 µl of internal standard solution for a total liquid volume of 10 ml. 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 Adsorption Stir at a temperature of 35 °C ± 2 °C for a minimum of 15 min in the vial open space. BS ISO 20752-2007 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 4 9.4 GC 9.4.1 Desorption Splitless injection for 2 min, at 250 °C (conditioning temperature of the 100 µm PDMS fibre). The fibre shall be conditioned between two extractions. 9.4.2 Chromatographic analysis The resolution grade and the time needed for the chromatographic separation shall be optimized by using a temperature program. EXAMPLE Temperature program: 50 °C for 2 min, from 50 °C to 150 °C at 9 °C/min, 0,5 min at 150 °C, from 150 °C to 260 °C at 20 °C/min, 260 °C for 5 min. 9.5 Detection 9.5.1 Determination by MS Detection either in selected ion monitoring (SIM) or in MS/MS mode with detection of 3 ions, and quantification through the most abundant ion. Ions are the following: For TCA: m/z 195, 210, 212, quantification with m/z 195. For TCA d5: m/z 199, 215, 217, quantification with m/z 215. The operating conditions in MS/MS mode are shown in Table 1 Table 1 Operating conditions in MS/MS mode Compound Precursor ion Product ion 2,4,6 TCA-d5 217 199 2,4,6 TCA 212 197 9.5.2 Determination by ECD Identify the analyte by comparing, on the chromatogram, the time retention of the sample peak to that of the standard peak. 9.6 Blank test Carry out a parallel test, without the stoppers in 9.2. 10 Expression of results Express concentration in nanograms per litre (ng/l). 2,4,6 TCA concentrations shall be rounded to the nearest whole number. BS ISO 20752-2007 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 5 11 Test report The test report shall include the following information: a) number of stoppers tested and volume of simulator used; b) a reference to this International Standard (ISO 20752); c) all data needed 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 2,4,6 TCA released, in nanograms per litre; g) detection limit and quantification limit; h) any incident likely to have affected the results, noted during the analysis; i) all optional operations or those not specified in this International Standard. BS ISO 20752-2007 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 6 Bibliography 1 ISO/IEC Guide 43-1, Proficiency testing by interlaboratory comparisons Part 1: Development and operation of proficiency testing schemes 2 ISO 2718, Standard layout for a method of chemical analysis by gas chromatography 3 NF V 03-1109 December 1998, Analysis of agri-foodstuffs Intralaboratory validation procedure for an alternative method compared to a reference method Case of quantitative analysis methods 4 G-CSQ-02, Guide for laboratories validating chemical analysis methods ENAC, Madrid 1996 5 Relacre Guide 13, February 2000, Validation of internal chemical analysis test methods 6 IUPAC Compendium of Chemical Terminology, 2nd edition 1997 BS ISO 20752-2007 Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Tue Jul 03 01:12:11 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS ISO 20752:2007 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. 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