NEUTRON-ACTIVATION ANALYSIS OF ARSENIC SPECIES

Inorganic arsenic, MMA, DMA and arsenobetaine (Asbeta) were separated by the use of cation and anion exchange chromatography combined with n eutron activation. Two complementary approaches were used: firstly aut hentic, non-irradiated arsenic compounds, either singly or in mixtures , were separated and NAA of the fractions used as an element specific detection method. Secondly, the arsenic compounds were neutron irradia ted under different conditions and for different times and the product s separated and quantified. The As-76 labeled species (mono-, di and t rimethylated) were then additionally used to calibrate and improve the column separations. Using the separations developed arsenic species i n samples of shrimps and the standard reference material DORM-1 were d etermined, after an extraction step, using ion exchange chromatography followed by INAA of the fractions collected.