1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 2561:2012Plastics Determination ofresidual styrene monomer inpolystyrene (PS) and impact-resistant polystyrene (PS-I) bygas chromatographyBS ISO 2561:2012 BRITISH STANDARD
2、National forewordThis British Standard is the UK implementation of ISO 2561:2012. Itsupersedes BS ISO 2561:2006 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/82, Thermoplastic materials.A list of organizations represented on this committee can beo
3、btained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 69436 3ICS 83.080.20Compliance wi
4、th a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 November 2012.Amendments issued since publicationDate Text affectedBS ISO 2561:2012 ISO 2012Plastics Determination of residua
5、l styrene monomer in polystyrene (PS) and impact-resistant polystyrene (PS-I) by gas chromatographyPlastiques Dtermination du styrne monomre rsiduel dans le polystyrne (PS) et le polystyrne rsistant au choc (PS-I) par chromatographie en phase gazeuseINTERNATIONAL STANDARDISO2561Third edition2012-11-
6、15Reference numberISO 2561:2012(E)BS ISO 2561:2012ISO 2561:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, incl
7、uding photocopying and microfilm, without permission in writing 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 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in
8、SwitzerlandBS ISO 2561:2012ISO 2561:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Reagents and materials . 15.1 Internal standard 15.2 Solvent 15.3 Precipitator 15.4 Aromatic hydrocarbons . 25.5 Carrier ga
9、ses and fuel gases for gas chromatograph . 26 Apparatus . 26.1 General . 26.2 Gas chromatograph . 26.3 Data processor 26.4 Sample injection syringe 26.5 Analytical balance. 26.6 Volumetric flasks . 27 Preparation of sample 28 Procedure. 28.1 General . 28.2 Preparation of internal-standard solution 3
10、8.3 Preparation of sample solution for method A 38.4 Preparation of sample solution for method B 38.5 Preparation of calibration solutions . 38.6 Gas-chromatographic procedure 49 Expression of results 69.1 Calculation of results from a calibration graph 69.2 Acceptability of results and measurement
11、sensitivity 710 Test report . 7Annex A (informative) Typical analytical conditions 9Annex B (informative) Correlation between mass of aromatic hydrocarbon in calibration solution and concentration of aromatic hydrocarbon in sample solution for typical calibration solutions used in method A and metho
12、d B .15Bibliography .16BS ISO 2561:2012ISO 2561:2012(E)ForewordISO (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.
13、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 Internat
14、ional 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 Standar
15、ds 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 o
16、f patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 2561 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 9, Thermoplastic materials.This third edition cancels and replaces the second edition (ISO 2561:2006), which has been tec
17、hnically revised. A second analytical condition (for a chromatograph with an open tubular column) using the solvent tetrahydrofuran has been added.iv ISO 2012 All rights reservedBS ISO 2561:2012INTERNATIONAL STANDARD ISO 2561:2012(E)Plastics Determination of residual styrene monomer in polystyrene (
18、PS) and impact-resistant polystyrene (PS-I) by gas chromatography1 ScopeThis International Standard specifies a method for the determination of the residual styrene monomer in polystyrene (PS) and impact-resistant polystyrene (PS-I) by gas chromatography. It may also be used for the simultaneous det
19、ermination of other volatile aromatic hydrocarbons in PS and PS-I.2 Normative referencesThe 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 docume
20、nt (including any amendments) applies.ISO 472, Plastics Vocabulary3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 472 apply.4 PrincipleThe polymer sample is dissolved in solvent, which for polystyrene contains an internal standard. Either a small volu
21、me of the polymer solution is injected directly into a gas chromatograph (method A) or a small volume of the supernatant solution remaining after precipitation of polymer by addition of a precipitator is injected (method B), in order to obtain separation of styrene and other volatile materials. Meth
22、od A is simple and has much the same accuracy as method B. However, there is a possibility that contamination of the injector with polymer and oligomers will occur over time, leading to erroneous results.5 Reagents and materials5.1 Internal standardThe internal standard shall be selected based on co
23、nsideration of the retention times of the materials contained in the polymer sample and solvent. Recommended candidates are n-butylbenzene, cyclopentanol, 1,2,4-trimetylbenzene and 1,4-diethylbenzene of sufficient purity for analytical use.5.2 SolventUse analytical-grade dimethylformamide, butanone,
24、 dichloromethane or tetrahydrofuran. Tetrahydrofuran is used for only method A.5.3 PrecipitatorUse analytical-grade 2,2,4-trimethylpentane or ethanol. ISO 2012 All rights reserved 1BS ISO 2561:2012ISO 2561:2012(E)5.4 Aromatic hydrocarbonsUse analytical-grade styrene and (if required) other aromatic
25、hydrocarbons such as ethylbenzene, cumene or -methylstyrene. Styrene shall give a clear mixture when mixed with an equal volume of ethanol.5.5 Carrier gases and fuel gases for gas chromatographUse helium or nitrogen as carrier gas. Use hydrogen and air as fuel gases.6 Apparatus6.1 GeneralNormal labo
26、ratory equipment and the following apparatus are required. Typical operating conditions are described in Annex A.6.2 Gas chromatograph6.2.1 Injection port: Use an injection port for liquid samples. When using an open tubular column (hereafter called an OT column), an injection port with splitter may
27、 be applicable.6.2.2 Column: The column diameter and length, as well as the packing material and liquid phase, shall be selected based on consideration of column resolution and calibration curve linearity. Both packed columns and OT columns are acceptable. OT columns are recommended in the light of
28、accuracy.6.2.3 Detector: Use a hydrogen flame ionization detector (FID).6.3 Data processorUse a recorder or microcomputer to record the signals from the detector.6.4 Sample injection syringeUse a micro-syringe of the 1 l to 50 l type. A micro-syringe forming part of the auto-injector may also be use
29、d.6.5 Analytical balanceA balance capable of measuring to 0,1 mg is required.6.6 Volumetric flasksVolumetric flasks are standardized in ISO 1042.7 Preparation of sampleThe sample can be taken from material in the form of powder, pellets or moulded parts. In order to ensure the desired accuracy of th
30、e sample mass, large pieces of sample shall be reduced to smaller fragments.8 Procedure8.1 GeneralDuring the dilution processes described below, the temperature of each solution shall remain under 25 C.2 ISO 2012 All rights reservedBS ISO 2561:2012ISO 2561:2012(E)8.2 Preparation of internal-standard
31、 solutionWeigh 200 mg of internal standard (5.1), to the nearest 1 mg, into a 1 000 ml volumetric flask (6.6). Then add solvent (5.2) to make exactly 1 000 ml, stopper tightly and mix well.8.3 Preparation of sample solution for method AWeigh 0,5 g of sample, to the nearest 1 mg, into a volumetric fl
32、ask (6.6) having a volume between 25 ml and 100 ml. Using a syringe or a pipette, add 20 ml of the internal standard solution prepared in 8.2. Then stopper tightly and mix until dissolved.8.4 Preparation of sample solution for method BWeigh 0,5 g of sample, to the nearest 1 mg, into a volumetric fla
33、sk (6.6) having a volume betwen 50 ml and 100 ml.Using either a syringe or a pipette, add 20 ml of the internal standard solution prepared in 8.2. Then stopper tightly and dissolve the sample (shake well, if necessary). After completely dissolving the sample, add 10 ml of precipitator (5.3) with a p
34、ipette. After vigorous shaking, allow the precipitate to settle. The supernatant solution is used for injection into the gas chromatograph using a micro-syringe (6.4).8.5 Preparation of calibration solutions8.5.1 GeneralThe range of concentrations which can be analysed by gas chromatography using th
35、e internal-standard method is determined by the amounts of measured styrene and other aromatic hydrocarbons to be measured and the dilutions (see Table 1). A series of calibration solutions are prepared for each aromatic hydrocarbon to be analysed. The solutions are kept for injection into the gas c
36、hromatograph.8.5.2 Calibration solutions for method AWeigh, to the nearest 0,1 mg, into separate volumetric flasks (6.6) (for the volume of the flasks, refer to Annex B) at least four of the amounts indicated in Table 1 of styrene and, if necessary, other aromatic hydrocarbons such as ethylbenzene,
37、cumene or -methylstyrene. Add internal-standard solution (8.2) to each flask, dissolve and make up to the mark with internal-standard solution.8.5.3 Calibration solutions for method BMeasure to the nearest 1 ml, 1 000 ml internal-standard solution (8.2) into a 2 000 ml flask. Then add 500 ml of prec
38、ipitator (5.3), stopper tightly and mix well (this solution is hereafter called the precipitator solution).Weigh, to the nearest 0,1 mg, into separate 1 000 ml volumetric flasks (6.6) at least four of the amounts indicated in Table 1 of styrene and, if necessary, other aromatic hydrocarbons such as
39、ethylbenzene, cumene or -methylstyrene. Add the precipitator solution to each flask, dissolve and make up to the mark with precipitator solution.NOTE For safety and economic reasons, there has been the case in which a smaller size glass container has been used instead of the 2 000 ml flask. ISO 2012
40、 All rights reserved 3BS ISO 2561:2012ISO 2561:2012(E)Table 1 Correlation between mass of aromatic hydrocarbon in calibration solution and concentration of aromatic hydrocarbon in sample solutionMass of aromatic hydrocarbon in 1 000 ml of calibration solutionCorresponding mass fraction of aromatic h
41、ydrocarbon in sample solution (sample = 0,5 g of polystyrene)mg g/g2,5 1005,0 20010,0 40020,0 80025,0 1 00050,0 2 0008.6 Gas-chromatographic procedure8.6.1 Gas-chromatograph operating conditionsSelect the gas-chromatographic conditions, solvent and internal standard to give sufficient separation of
42、styrene and the other eluted materials. If it is difficult to separate the peak corresponding to the internal standard from that corresponding to a target component, except styrene, use the standard addition method for analysis. If it is difficult to separate the peak corresponding to the internal s
43、tandard from those due to impurities, increase the concentration of the internal standard to a level at which the peaks due to impurities become negligible.Prepare a chromatogram satisfying the following requirements. The resolution Rebetween the peaks corresponding to styrene, the internal standard
44、 and any other aromatic hydrocarbons (such as ethylbenzene, cumene or -methylstyrene) and the peaks corresponding to the target components appearing just before or just after the former peaks shall be more than 1,0 and preferably 1,5 if possible. The resolution Rebetween two peaks with the same area
45、 is defined as follows:Re= 2(t2- t1)/(W1+ W2) wheret1and t2are the retention times of the two peaks; W1and W2are the respective widths of the peaks.The gas-chromatographic conditions are chosen to give the above performance. Representative conditions are described below, and more detailed conditions
46、 for each method and column are described in Annex A.4 ISO 2012 All rights reservedBS ISO 2561:2012ISO 2561:2012(E)Column: Metal, glass tubing and fused silica capillary are typical. Packed column: Pack with a commercial packing material and allow sufficient stabilization before use.OT column: Choos
47、e a commercial OT column coated with a suitable station-ary phase inside of the tube and allow sufficient time for it to stabilize before use.Column temperature: isothermal or rising temperatureIt is not regulated, but rising temperature condition is recom-mended in the light of time saving.Temperat
48、ure of injection port: 200 C to 250 CTemperature of detector: 200 C to 250 CCarrier gas: Helium or nitrogenCarrier gas flow rate: Packed column: 25 cm3/min to 90 cm3/min.OT column: 2,5 cm3/min to 10 cm3/min.FID: Adjust the hydrogen and air flow rates to give: a high sensitivity of response; a linear
49、 response over the range of concentrations being measured; only insignificant effects of small changes in flow rate on response or sensitivity.NOTE Use of method A may cause deposition of polymer on the column, making more frequent changes of the column necessary.8.6.2 Recording the gas chromatograms of sample solutions and calibration solutionsDepending on the sensitivity of the gas chromatograph used, inject a suitable volume of the sample solution (prepared in accordance with 8.3 or 8.4) or the calibration solutions (prepar
