The influence of chelating reagents on plumbane generation: Determination of lead in the presence of PAN-S.

A series of 22 chelating reagents were tested for plumbane generation. Besides nitroso R salt, the reagents Bromo Pyrogallol Red, Pyrocatechol Violet, Alizarine Red-S, 5-Br-PADAP and PAN-S could significantly enhance the lead signal. The PAN-S system has been optimized. The characteristic concentration (5 ml sample) is 1.3 ng/ml, and the RSD at the 50 ng/ml level is 3.9%. Lead spiked into tap water and natural water was determined by HG-AAS in the presence of PAN-S. Recoveries of spiked lead were between 90 and 105 %. Study of the mechanism suggests that the lead hydride might be directly generated from the chelated Pb(II) instead of the metastable Pb(IV).