【国外标准】 Standard Practice for Hotplate Digestion of Lead from Composited Wipe Samples

5.1 This practice is for use in the preparation of no more than four wipe samples combined to form a composited sample for subsequent determination of lead content.5.2 This practice assumes use of wipes that meet Specification E1792 and should not be used unless the wipes meet Specification E1792.5.3 This practice is capable of preparing samples for determination of lead bound within paint dust.5.4 This practice may not be capable of preparing samples for determination of lead bound within silica or silicate matrices, or within matrices not soluble in nitric acid.5.5 Adjustment of the nitric acid concentration or acid strength, or both, of the final extract solution may be necessary for compatibility with the instrumental analysis method to be used for lead quantification.5.6 This sample preparation practice has not been validated for use and must be validated by the user prior to using the practice for client samples.NOTE 1: Each combination of wipes (two wipes, three wipes, and four wipes) constitutes a different matrix and must be separately validated.1.1 This practice is similar to Practice E1644 and covers the hot, nitric acid digestion of lead (Pb) from a composited sample of up to four individual wipe samples of settled dust collected from equally-sized areas in the same space.1.2 This practice contains notes which are explanatory and not part of mandatory requirements of the practice.1.3 This practice should be used by analysts experienced in digestion techniques such as hot blocks. Like all procedures used in an analytical laboratory, this practice needs to be validated for use and shown to produce acceptable results before being applied to client samples.1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.1.5 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.1.6 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.