A method has been developed for the determination of lead, cadmium, cobalt, tin, copper, arsenic, and molybdenum in seawater and biol. samples by graphite furnace atomic absorption spectrometry after precipitation with ammonium pyrrolidinedithiocarbamate (APDC). Biol. samples were digested with a mixture of nitric and perchloric acid. The recommended precipitation conditions used in real sample analyses were defined as 1.0 mol dm-3 HNO3 for Mo, 0.5 mol dm-3 HClO4 for Co, and 1.0 mol dm-3 HClO4 for the other elements as well as 2 mL of 2% APDC aqueous solution if the total vol. of solution was 7.0 mL. When the precipitation procedure was completed the supernatant solution was sucked out and metal-PDC ppt. complexes were dissolved in 0.5 mL MIBK. The organic phase was washed with 2 mL of deionized water and stored together with the aqueous phase for the determination To reduce and/or eliminate the interference from trace amts. of HClO4 in the organic phase. Pd, ascorbic acid, or (NH4)2SO4 were used as matrix modifiers for the determination of Pb, Sn, and As, resp. No matrix modification was used for determing the other elements. Good recovery was achieved for nanograms of Pb, Cd, Co, Cu, Sn, As, and Mo spiked to seawater samples. The method has been applied for determing elements in seawater and biol. standard ref. materials; the results were in good agreement with certified values.

Key words: COBALT, ATOMIC ABSORPTION SPECTROPHOTOMETRY, COPPER, ARSENIC, SEA WATER, CADMIUM, LEAD, TIN, MOLYBDENUM, CONCENTRATION