1、BRITISH STANDARD BS ISO 13741-2:1998 Plastics/rubber Polymer dispersions and rubber latices (natural and synthetic) Determination of residual monomers and other organic components by capillary column gas chromatography Part2: Headspace method ICS83.040.10;83.080.01BSISO13741-2:1998 This British Stan
2、dard, having been prepared under the directionof the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 June 1998 BSI 04-1999 ISBN 0 580 29968 6 National foreword This British Standard reproduces verbatim ISO13741-2:1998 and
3、 implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee PRI/21, Testing of plastics, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on th
4、e interpretation, or proposals for change, and keep the UKinterests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standar
5、ds which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard
6、does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an i
7、nside front cover, pages i and ii, theISO title page, pagesii to iv, pages 1 to6 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publicatio
8、n Amd. No. Date CommentsBSISO13741-2:1998 BSI 04-1999 i Contents Page National foreword Inside front cover Foreword iii Test of ISO13741-2 1ii blankBSISO13741-2:1998 ii BSI04-1999 Contents Page Foreword iii Introduction 1 1 Scope 1 2 Normative reference 1 3 Principle 1 4 Reagents 1 5 Apparatus 2 6 P
9、reparation of apparatus 2 7 Calibration 2 8 Procedure 2 9 Calculation 3 10 Precision 3 11 Test report 3 Figure 1 4 Figure 2 5 Figure 3 6 Table 1 Typical operating conditions 3BSISO13741-2:1998 BSI 04-1999 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation
10、 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.
11、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. Draft International Standards adopted by the technica
12、l committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO13741-2 was prepared by Technical Committee ISO/TC61, Plastics, Subcommittee SC9, Thermoplastic materi
13、als, in close collaboration with ISO/TC45, Rubber and rubber products. ISO13741 consists of the following parts, under the general title Plastics/rubber Polymer dispersions and rubber latices (natural and synthetic) Determination of residual monomers and other organic components by capillary-column
14、gas chromatography. Part1: Direct liquid injection method; Part2: Headspace method. Descriptors: Plastics, polymers, rubber, latex, aqueous dispersions, chemical analysis, determination of content, organic compounds, monomers, gas chromatography, capillary columns.iv blankBSISO13741-2:1998 BSI 04-19
15、99 1 Introduction The requirements imposed today by authorities include the assessment of the content of residual monomers and organic saturated volatiles, for health and environmental reasons sometimes down to minute traces. Former standards for measurement of residual volatiles based on distillati
16、on linked with titration cannot cope with such exigences. This part of ISO13741 presents an advanced method for the determination by gas chromatography, of residual monomers and other organic components in polymer dispersions and latices. This standard provides a method that is in line with present-
17、day requirements for analytical methods and is intended for use instead of ISO2008:1987, Rubber latex, styrenebutadiene Determination of volatile unsaturates and ISO3899:1988, Rubber Nitrile latex Determination of residual acrylonitrile content, where precise measurements of volatile-matter content
18、are needed, and expands their scope to include other volatile organic components. WARNING This part of ISO13741 does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this part of ISO13741 to establish appropriate safety and h
19、ealth practices and determine the applicability of regulatory limitations prior to use. 1 Scope 1.1 This part of ISO13741 specifies a method for the determination of residual monomers and other (unsaturated or saturated) organic components in aqueous polymer dispersions and latices as well as in rel
20、ated products. It makes use of capillary-column gas chromatography, the sample being introduced into the chromatograph in vapour form from a headspace vial. 1.2 Residual monomers and saturated volatiles that have been successfully determined by this method include acrylic and methacrylic esters, but
21、adiene, styrene and vinyl acetate, as well as by-products such as ethylbenzene. 1.3 Since the chromatograms obtained normally contain a series of peaks, it is only possible to determine the content of those volatiles for which response factors have been determined. For the identification of unknown
22、peaks, auxiliary methods like mass spectroscopy or the use of a second GC column with a different polarity are advisable. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this part of ISO13741. At the time of publication
23、, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this part of ISO13741 are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently
24、 valid International Standards. ISO3696:1987, Water for analytical laboratory use Specification and test methods. 3 Principle A suitable aliquot of the sample is diluted with water and with a water-miscible solvent containing an internal standard and a polymerization inhibitor. The mixture is introd
25、uced into a headspace vial and the vial sealed. The vial is allowed to come to thermal equilibrium and a measured quantity of the headspace vapours is introduced into a gas chromatograph with a capillary column, a flame ionization detector and a linear temperature programming capability. Sample intr
26、oduction is achieved using commercially available automatic equipment. 4 Reagents Unless otherwise stated, use only reagents of recognized analytical grade (purity99%) and only grade1 water as defined in ISO3696. 4.1 Carrier gas: helium or nitrogen. 4.2 Dioxane, for use as an internal standard. Diox
27、ane is one of several suitable internal standards. Other organic compounds not found in the sample could also be used (e.g.methyl iso-butyl ketone). The internal standard shall not co-elute with any of the compounds of interest. Its retention time shall lie within the range covered by the compounds
28、of interest. 4.3 Monomers, 99% purity, for comparison purposes. 4.4 Dimethylacetamide or dimethylformamide. 4.5 2,6-Di-tert-butyl-4-methylphenol, for use as a polymerization inhibitor.BSISO13741-2:1998 2 BSI 04-1999 5 Apparatus Ordinary laboratory equipment, plus the following: 5.1 Gas chromatograph
29、, having an injection port designed for split operation, a flame ionization detector (FID) and a linear temperature programming capability for the column, and capable of sequentially sampling and analysing the headspace vapours contained in sealed headspace vials. 5.2 Capillary column, of length30m
30、and internal diameter0,25mm, made of fused silica that is covered inside with a14m thick film of a dimethylpolysiloxane. 5.3 Integrator. 5.4 Autosampler vials, capacity approx.20cm 3 , suitable for headspace chromatography. 5.5 Aluminium- or PTFE-coated septa and aluminium caps, for sealing the vial
31、s. 5.6 Cap crimper. 5.7 Analytical balance, accurate to0,1mg. 5.8 Magnetic stirrer or roller mixer. 6 Preparation of apparatus 6.1 Condition the column by attaching one end of the column to the inlet side of the apparatus, leaving the exit end of the column disconnected. This prevents contamination
32、of the detector due to column bleed. Set the carrier gas flow rate to the value given in the instruction manual and purge the column at220 C for1h (or longer). 6.2 After conditioning, connect the exit end of the column to the detector and establish the operating conditions required to give the desir
33、ed separation (for typical conditions, see Table 1). Allow sufficient time for the apparatus to reach equilibrium as indicated by a stable baseline. 6.3 Control the detector temperature so that it is constant to within1 C, without thermostat cycling which causes an uneven baseline. 7 Calibration 7.1
34、 For reliable results, it is necessary to calibrate the instrument for each analysis with respect to sensitivity and retention time. This is done by determining the response factors and retention times for each component expected to be present in the dispersion or the latex by analysing the headspac
35、e above a solution of an internal standard together with the individual components, or mixtures thereof, dissolved in a solvent (e.g.dimethylacetamide). Use the same instrument conditions as for sample analysis. 7.2 Mix1cm 3of water with2cm 3of internal standard solution (containing about5004g of di
36、oxane per1cm 3of dimethylacetamide) and a small volume(504l) of a mixture of the volatiles of interest in which the mass fractions of the volatiles of interest are in proportion to the mass fractions in the sample. It is advisable to perform the calibration procedure at different concentration level
37、s (three or four different concentrations are recommended). 7.3 Measure the peak areas of the individual components and calculate the relative response factor R ffor each component as follows: where 7.4 Calculate the mean response factor for each volatile. 7.5 Repeat this calibration as needed. 7.6
38、Typical response factors are: NOTER fvalues depend strongly on the column used. 8 Procedure 8.1 Weigh, to the nearest0,2mg, about0,5g of the sample into a headspace vial. Add1cm 3of water and2cm 3of internal standard solution (containing about5004g of dioxane per1 cm 3of dimethylacetamide), cover wi
39、th a septum and seal the vial so that it is pressuretight. NOTEDepending on the type of polymer and the analyte concerned, other high-boiling solvents that are miscible with water can also be used. R f is the response factor for the volatile of interest relative to the internal standard; A S is the
40、peak area of the internal standard; A V is the peak area of the volatile of interest; is the mass of the internal standard in the calibration mixture; is the mass of the volatile of interest in the calibration mixture. ethylbenzene approx.0,1 styrene approx.0,2 4-phenylcyclohexene approx.1 R f A S m
41、 V A V m S - = m S m VBSISO13741-2:1998 BSI 04-1999 3 Table 1 Typical operating conditions a 8.2 Homogenize the sample solution by stirring with a magnetic stirrer for30min to4h, depending on the composition, or by rolling the vials on a roller mixer for24h. 8.3 Heat the sample solution at90 C for1h
42、 to equilibrate the system and analyse the headspace vapours under the conditions given in clause6. 8.4 Measure the peak areas of the internal standard, A S , and of the relevant volatiles, A V . 9 Calculation Calculate the mass fraction w V , in milligrams per kilogram, of each volatile present in
43、the polymer dispersion/latex as follows: where NOTEIn special cases, calculation by the standard additions method or the multiple headspace extraction method may be more suitable. Typical chromatograms are shown in Figure 1 to Figure 3. Report results which are lower than10mg/kg (the detection limit
44、) as10mg/kg. 10 Precision The precision of this test method is not known because inter-laboratory data are not available. 11 Test report The test report shall include at least the following information: a) a reference to this part of ISO13741; b) the results obtained, calculated in accordance with c
45、lause9; c) the operating conditions used, if different from those in Table 1; d) the date of the test. Detector flame ionization The hydrogen, air and make-up gas (e.g.nitrogen) flow rates shall be optimized in accordance with the advice of the FID manufacturer Column Length 30m Inside diameter 0,25
46、mm Film thickness 1 4m (dimethylpolysiloxane) Carrier gas helium or nitrogen Column pressure 0,7MPa to1,7 MPa Split 25cm 3 /min Temperatures Detector block 300 C Initial column temperature 50 C Hold time 5min Programme rate 5 C/min Final column temperature 260 C Final hold time 10min Injection time/
47、volume 6s in the case of pressure-programmed sampling 1ml in the case of sample-loop technique a It may be necessary to modify these conditions if separation problems are encountered or if other conditions are specified in the gas chromatograph manufacturers instructions. For instance, a column with
48、 an inside diameter0,25mm may be more suitable: in this case, reduce the carrier gas flow rate to ca.1cm 3 /min. A V is the peak area of the volatile of interest; A S is the peak area of the internal standard; m S is the mass, in milligrams, of internal standard in the sample solution prepared in8.1
49、; m d is the mass, in kilograms, of sample in the sample solution prepared in8.1; w V A V m S R f A S m d - = R f is the response factor for the volatile of interest, determined in accordance with7.3.BSISO13741-2:1998 4 BSI 04-1999 Figure 1 BSISO13741-2:1998 BSI 04-1999 5 Figure 2 BSISO13741-2:1998 6 BSI 04-1999 Figure 3 blankBS ISO 13741-2:1998 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible fo
