Determination of submicrogram amounts of mercury in various matrices by flameless atomic-fluorescence spectrometry

Abstract

An atomic-fluorescence spectrometric method is described for the determination of mercury at the nanogram level. Solid samples are burnt in an oxygen stream, the combustion gases being condensed in a liquid nitrogen cooled trap. Following the dissolution of the condensed matter, mercury is extracted by the reduction-aeration method and collected on gold, forming an amalgam. The combination of a high-efficiency light-gathering system with a gas-shielded windowless fluorescence cell, and the described procedure for the release of mercury vapour from the amalgam, allows a detection limit of 0.03 ng to be obtained. A linear working graph covering the concentration range of mercury from 0.5 to 100 ng was established with aqueous standard solutions of mercury.The whole procedure has been checked with two different NBS Standard Reference Materials, excellent agreement of the measured values with the certified values being found.