【国外标准】 Standard Test Method for Acetone, p-Chlorobenzotrifluoride, Methyl Acetate or t-Butyl Acetate Content of Solventborne and Waterborne Paints, Coatings, Resins, and Raw Materials by Direct Injection Into a Gas Chromatog

4.1 With the need to calculate volatile organic content (VOC) of paints, and with acetone, p-chlorobenzotrifluoride, methyl acetate and t-butyl acetate4 considered as exempt volatile compounds, it is necessary to know the content of these analytes. This gas chromatographic test method provides a relatively simple and direct way to determine their content. However, because the detectors used in this test method are not selective, and because some coatings are very complex mixtures, compounds may be present in the sample that coelute with the analyte, giving a result that is erroneously high. Or a component may elute with the internal standard, giving a result that is erroneously low. It is therefore important to know the composition of the sample to ensure that there are no interferences, under the analysis conditions used. Test Method D6438 employs mass-spectral detection of analytes and may be used as an alternative method.1.1 This test method is for the determination of the total-concentration of acetone, p-chlorobenzotrifluoride, methyl acetate, or t-butyl acetate, or combination of any of the four, in solvent-reducible and water-reducible paints, coatings, resins, and raw materials. Because unknown compounds that co-elute with the analyte being measured or with the internal standard, will lead to erroneous results, this test method should only be used for materials of known composition so that the possibility of interferences can be eliminated. The established working range of this test method is from 1 % to 100 % for each analyte by weight.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.