Sampling of atmospheric Hgo using home-made gold-coated sand sorbent prior to analysis by atomic absorption spectrometry

Abstract

Gold-coated sand for amalgamation was synthesized and applied for the determination of mercury in ambient air using a home-made dual gold trap unit coupled to atomic absorption spectrometer. Gold-coated sand is prepared by chemical reduction of Au(III) solution with hydroxylamine depositing elemental gold on acid-etched sand. A home-made dual gold trap unit which focused time-resolved mercury trapped from the sampling/first trap provided an increase in sensitivity and reliability for the analysis of ultra-trace mercury in air was designed and tested. Instrumental detection and quantitation limits (IDL and IQL) of system were 3.9 and 13pg Hg, respectively. Method detection and quantitation limits (MLOD and MLOQ) of system were 0.04 and 0.13ngHg.m^-3 for sampling flow rate of 200mL.min^-1 and sampling time of 8 hours. Sampling system for gaseous elemental mercury was set up and cooperated with home-made desorption system were preliminarily applied for analysis of atmospheric mercury in samples collected at Hochiminh city University of Science. The atmospheric mercury concentrations were in range of 2.7 – 8.1ng Hg. m^-3 which were comparable to Hg concentration found in other cities in the world.