空气中铅测量-美国EPA空气中悬浮颗粒物种铅测量规范

Appendix G to Part 50—Reference Method for the Determination of Lead in Suspended Particulate Matter Collected From Ambient Air 1. Principle and applicability. 1.1 Ambient air suspended particulate matter is collected on a glass-fiber filter for 24 hours using a high volume air sampler. The analysis of the 24-hour samples may be performed for either individual samples or composites of the samples collected over a calendar month or quarter, provided that the compositing procedure has been approved in accordance with section 2.8 of appendix C to part 58 of this chapter—Modifications of methods by users. (Guidance or assistance in requesting approval under Section 2.8 can be obtained from the address given in section 2.7 of appendix C to part 58 of this chapter.) 1.2 Lead in the particulate matter is solubilized by extraction with nitric acid (HNO3), facilitated by heat or by a mixture of HNO3 and hydrochloric acid (HCl) facilitated by ultrasonication. 1.3 The lead content of the sample is analyzed by atomic absorption spectrometry using an air-acetylene flame, the 283.3 or 217.0 nm lead absorption line, and the optimum instrumental conditions recommended by the manufacturer. 1.4 The ultrasonication extraction with HNO3/HCl will extract metals other than lead from ambient particulate matter.