【国外标准】 Standard Test Method for Analysis of Aqueous Extractable Protein in Latex, Natural Rubber, and Elastomeric Products Using the Modified Lowry Method

5.1 This test method, for the determination of protein levels in latex, is primarily intended to test NR, latex, and elastomeric materials for residual protein content. It is assumed that all who use this test method will be trained analysts capable of performing common laboratory procedures skillfully and safely. It is expected that work will be performed in a properly equipped laboratory.1.1 This test method covers an analytical test for determining the amount of total aqueous extractable protein associated with NR, latex, and elastomeric products. Water soluble proteins are extracted in a buffer solution and then precipitated to concentrate them and also to separate them from water soluble substances that may interfere with the determination. The extracted protein is redissolved and quantified colorimetrically by the modified Lowry method using a protein standard.1.2 For the purpose of this test method, the range of protein measurement will be based on the limit of detection and quantitation and recorded in micrograms per dm2 test specimen.1.3 The test method is designed to be accurate and compatible with the industrial environment.1.4 Steps are included in this test method to minimize the effects of interfering substances.1.5 It is recognized that other methods for the analysis of leachable proteins exist and these may be used for routine quality control purposes provided they have been validated and a correlation established against the reference method specified by this test method.1.6 This test method has not been validated for use with lubricated products such as condoms. Condoms with different lubricants as typically marketed, have not been tested in an ASTM ILS to determine if, and if so to what degree, the lubricant interferes with the assay.1.7 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.1.8 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.