Simple and sensitive determination of arsenic by volatile arsenic trichloride generation atomic fluorescence spectrometry

A simple, sensitive and interference-free method was proposed for the determination of arsenic, based on the generation of volatile arsenic trichloride coupled with atomic fluorescence spectrometry. Thiourea, together with L-ascorbic acid, was used to reduce As(V) to As(III), and the chloride generation was based on the reaction between As(Ill) and hydrochloric acid. Under the optimized experimental conditions, the present procedure allows for the quantification of arsenic in the concentration range of 0.01-4.0 mg L-1, with a limit of detection (3 sigma) of 6.0 mu g L-1. The relative standard deviation (R.S.D.) is 4.0% for 0.1 mg L-1 arsenic (n = 7). Finally, the proposed method was successfully applied to the determination of arsenic in several certified reference samples (stainless steel, alloy steel, copper alloy and water sample) and real samples (brass material and spiked cobalt material), with analytical results well-agreed with those by ICP-MS. (C) 2007 Published by Elsevier B.V.