ARSENIC AND ANTIMONY DETERMINATION IN SOILS AND SEDIMENTS BY GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY WITH SLURRY SAMPLING

Slurry-based procedures for the rapid determination of arsenic and ant imony in soil and sediment samples by graphite furnace atomic absorpti on spectrometry are discussed. For the determination of arsenic, the s amples are suspended in a solution containing dilute hydrofluoric acid . Sodium hydrogen carbonate is added and aliquots are introduced into the graphite furnace. A fast heating programme with no pyrolysis step is used. For the determination of antimony, direct suspension in conce ntrated hydrofluoric acid is recommended. In this way, the interferenc e of silicon is avoided and the background level is reduced, allowing a fast heating programme to be used. The limit of detection of antimon y for a 100 mg ml(-1) suspension is 0.03 mu g g(-1). The results obtai ned for five certified reference materials using both direct calibrati on against aqueous standards and the standard additions method demonst rate the reliability of the procedures. (C) 1997 Elsevier Science B.V.