1、 Reference number ISO 17736:2010(E) ISO 2010INTERNATIONAL STANDARD ISO 17736 First edition 2010-12-15 Workplace air quality Determination of isocyanate in air using a double-filter sampling device and analysis by high pressure liquid chromatography Qualit de lair des lieux de travail Dosage des isoc
2、yanates dans lair au moyen dun dispositif dchantillonnage filtre double et par analyse par chromatographie liquide haute performance ISO 17736:2010(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall
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6、m or by any means, electronic or mechanical, including 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 office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09
7、47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2010 All rights reservedISO 17736:2010(E) ISO 2010 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1 2 Normative references1 3 Principle.1 4 Reagents and materials 2 5 Apparatus.3 6 Air sampling.4 6.1 C
8、alibration of sampling system .4 6.2 Preparation of sampling equipment4 6.3 Preparation of MAMA-impregnated filter 4 6.4 Collection of samples .4 6.5 Blanks.5 7 Procedure.5 7.1 Safety precautions 5 7.2 Calibration standard5 8 Sample processing6 8.1 Vapour analysis .6 8.2 Aerosol analysis 6 9 HPLC co
9、nditions7 9.1 General .7 9.2 HPLC conditions vapour isocyanates 7 9.3 HPLC conditions aerosol isocyanates .7 10 Analysis8 10.1 Calibration curve .8 10.2 Quality control .8 10.3 Sample quantification .8 11 Interference 9 12 Determination of performance characteristics 10 12.1 Introduction10 12.2 Rele
10、vant uncertainty contributions and criteria 10 12.3 Assessment of performance characteristics, following the detailed approach in ISO/IEC Guide 98-3 5 11 Annex A (informative) Performance characteristics .18 Annex B (informative) Sample chromatograms.20 Bibliography27 ISO 17736:2010(E) iv ISO 2010 A
11、ll rights reservedForeword 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 sub
12、ject 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 (I
13、EC) 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 commit
14、tees 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
15、 held responsible for identifying any or all such patent rights. ISO 17736 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 2, Workplace atmospheres. ISO 17736:2010(E) ISO 2010 All rights reserved vIntroduction Isocyanates are commercially available chemicals used in the
16、polyurethane industry. They are known to cause health problems, such as asthma, contact dermatitis and hypersensitivity pneumonitis, in workers even at very low levels in occupational environments. Since isocyanates are highly reactive compounds and exposure limits are very low, the sampling and the
17、 analysis of these substances are critical. This method is based on the standard method developed by the Institut de Recherche en Sant et en Scurit du Travail Occupational Health and Safety Research Institute (IRSST) of Quebec. It has been in use for more than 18 years as the standard government met
18、hod in that province of Canada. Since 1996, it has been introduced into the marketplace in the USA, Brazil, and the UK. After a years study (Reference 10), the method was adopted in 1998-11 by the US Air Force as an acceptable alternative to NIOSH Method 5521 for monomeric isocyanates (now withdrawn
19、). The method is now routinely used in the Canadian provinces of Alberta, British Columbia, and Ontario, and in the US state of Washington, which has validated the method for TDI. Thirteen laboratories have been schooled in this analytical method, three in Canada, eight in the USA and Mexico, one in
20、 Brazil, and one in the UK. This method has been in use in several countries for many years and 13 laboratories participate in round robin testing on a regular basis in order to maintain their proficiency. The double-filter method has been validated for different applications of isocyanates such as
21、spray-painting (Reference 11) and foam manufacturing. It has also been compared with other established methods and demonstrated equivalent results (Reference 10). Double-filter methods are also available in ASTM D6561 7and ASTM D6562 8for HDI, and ASTM D5932 9for TDI. ISO draws attention to the fact
22、 that it is claimed that compliance with this document may involve the use of a patent concerning the double-filter sampling device for isocyanates. INTERNATIONAL STANDARD ISO 17736:2010(E) ISO 2010 All rights reserved 1Workplace air quality Determination of isocyanate in air using a double-filter s
23、ampling device and analysis by high pressure liquid chromatography 1 Scope This International Standard gives general guidelines for the sampling and analysis of airborne isocyanates in workplace air. This International Standard is appropriate for organic compounds containing free isocyanate function
24、al groups and is specific for the quantification of monomers, polymers and prepolymers, vapours and aerosols. Differential air sampling is performed with a segregating device which can show the physical state of the isocyanates analysed as found in the field. This capacity, however, may show limitat
25、ions for given situations, e.g. when aerosols collected on the first filter contain free monomer that migrates to the second filter and is then quantified as vapour phase isocyanate. The determination of aromatic monomers includes toluene diisocyanate (TDI) and 4,4-diisocyanato-diphenylmethane (MDI)
26、. Aliphatic monomers include isophorone diisocyanate (IPDI), 4,4-methylene bis-(cyclohexyl isocyanate) (HMDI) and 1,6-hexamethylene diisocyanate (HDI). Isocyanate oligomers and prepolymers can also be determined using this method. The double-filter method is designed to determine short-term (15 min)
27、 exposure concentrations of organic isocyanates in a workplace environment by personal monitoring or by fixed location monitoring. However, if the exposure is expected to be in vapour form only, then sampling time can be extended to 8 h. Since the filter is derivatized in the field immediately after
28、 sampling, loss of isocyanate aerosol because of its reaction with other chemicals is negligible except for very fast-reacting isocyanate systems such as foam spraying of MDI in polyurethane applications. The method is suitable for the measurement of airborne organic isocyanates in the NCO equivalen
29、t concentration range of 0,01 g/sample to 2,1 g/sample, corresponding to approximately 0,67 g/m 3to 140 g/m 3for a 15 l sample volume. This range brackets about eight times the current established threshold limit value (TLV) of 5 ppb for monomers set by many national authorities. 2 Normative referen
30、ces 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 5725-2, Accuracy (trueness and precision)
31、 of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method EN 1232, Workplace atmospheres Pumps for personal sampling of chemical agents Requirements and test methods 3 Principle A measured volume of air is dra
32、wn through a double-filter sampling device in which the first filter made of polytetrafluoroethylene (PTFE) collects the aerosols and then the isocyanate vapour is absorbed on a glass fibre (GF) filter impregnated with 9-(methylaminomethyl)anthracene (MAMA). The isocyanate present as an aerosol is c
33、ollected on the PTFE filter and derivatized immediately after sampling, in a 5 ml solution of 1-(2-methoxyphenyl)piperazine (MP), 0,1 mg/ml in toluene. ISO 17736:2010(E) 2 ISO 2010 All rights reservedBoth isocyanate monomer and oligomer urea derivatives solutions are separated using reversed phase h
34、igh performance liquid chromatography (HPLC). Vapour monomers are analysed by HPLC using an ultraviolet (UV) and fluorescence (FL) detector. Fluorescence detection is used when concentrations are less than 25 % of the TLV. Monomeric and oligomeric aerosols are analysed by HPLC with a UV detector for
35、 quantification and a diode array detector (DAD) for identification. Quantification of the monomeric aerosols is made by comparison with the relevant isocyanate monomer standard. The total isocyanate-in-air concentration is calculated from the sum of all the isocyanate-derived peaks calculated as NC
36、O function. In some cases, a bulk sample is used for calibration and results are reported as mass of base per volume. The quantitative detection limits for isocyanate, defined as 10s, where s is the standard deviation obtained from 10 measurements carried out on a standard solution whose concentrati
37、on is close to the expected detection limit, has been estimated to be approximately 0,026 g/sample, 0,029 g/sample, and 0,036 g/sample for vapour phase HDI, TDI, and MDI, respectively. The quantitative detection limit for aerosol phase HDI, TDI, and MDI is 0,031 g/sample. NOTE The calculation of oli
38、gomeric isocyanates by this method is expressed as the total NCO function equivalent, utilizing the response factor of the corresponding monomer for the oligomer calculation. 4 Reagents and materials During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and d
39、istilled or demineralized water or water of equivalent purity. 4.1 Water, HPLC grade or equivalent. 4.2 1-(2-Methoxyphenyl)piperazine (MP) CAS No. 35386-24-4, 98 % mass fraction. 4.3 9-(Methylaminomethyl)anthracene (MAMA) CAS No. 73356-19-1, 99 % mass fraction. 4.4 Acetic acid, glacial CAS No. 64-19
40、-7, HPLC grade. 4.5 Acetic anhydride CAS No. 108-24-7, certified ACS. 4.6 Triethylamine CAS No. 121-44-8, 98 % mass fraction assay by GC. 4.7 Phosphoric acid CAS No. 7664-38-2, certified ACS. 4.8 Reagent solvents, commonly toluene CAS No. 108-88-3, dimethylformamide CAS No. 68-12-2, and acetonitrile
41、 CAS No. 75-05-8, should be HPLC grade. They shall be free from compounds co-eluting with the substance(s) of interest. To avoid any interference from the solvent, perform quality controls on each different lot of solvent. 4.9 Buffer solution and HPLC mobile phase. 4.9.1 Triethylamine buffer vapour
42、analysis. In a 1 l volumetric flask, dilute 30 ml triethylamine (4.6) in water, and make up to the mark with water. Adjust the pH of this solution to 3 using phosphoric acid (4.7). Filter the solution under vacuum with a 0,22 m filter. 4.9.2 Sodium acetate buffer aerosol analysis. Weigh approximatel
43、y 12,5 g of sodium acetate in 1 l HPLC grade water (4.1). Adjust the pH of this solution to 6 with glacial acetic acid (4.4). Filter the resulting solution under vacuum with a 0,22 m filter. 4.9.3 Mobile phase vapour analysis. A solvent mixture of acetonitrile (4.8) and triethylamine buffer (4.9.1).
44、 The appropriate proportion of each solvent depends on the isocyanate analysed, see Table 1. 4.9.4 Mobile phase aerosol analysis. A solvent mixture of acetonitrile (4.8) and sodium acetate buffer (4.9.2). The appropriate proportion of each solvent depends on the isocyanate analysed, see Table 2. ISO
45、 17736:2010(E) ISO 2010 All rights reserved 34.10 Reagent solutions. 4.10.1 Desorption solution vapour analysis. A solvent mixture of 67 % volume fraction of dimethylformamide (4.8) and 33 % volume fraction mobile phase. 4.10.2 Derivatization solution aerosol analysis. Weigh 10 mg MP (4.2) and trans
46、fer it to a 100 ml volumetric flask. Dissolve and make up to the mark with toluene (4.8). The final concentration of this MP solution is equivalent to 0,1 mg/ml. 5 Apparatus 5.1 Sampling system. A three-piece, closed face, 37 mm cassette is used. The sampling train consists of a 37 mm PTFE filter of
47、 porosity 5 m followed by a binder free 37 mm glass fibre (GF) filter impregnated with MAMA (4.3) and supported by a cellulose back-up pad (see Figure 1). Figure 1 Three-piece cassette 37 mm This sampling train is commercially available as ISO-CHEK 1) . 5.2 Sampling pump. The pump shall fulfil the r
48、equirements of EN 1232 or equivalent. The pump should also be in accordance with local safety regulations. 5.3 Tubing, of plastic, rubber or other suitable material, about 900 mm long, of appropriate diameter to ensure a leakproof fit to both pump (5.2) and double-filter sampling cassette (5.1). Cli
49、ps shall be provided to hold the cassette and connecting tubing to the workers lapel within 300 mm of their breathing zone. 5.4 Flow meter, portable, capable of measuring the appropriate flow rate to within 5 %, and calibrated against a primary standard. 1) ISO-CHEK is the trade name of a product supplied by SKC. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of the product named. Equivalent prod
