Valence states of arsenic and antimony in sea water

A simple and convenient chemical procedure for the determination of As(III), As(V), Sb(III) and Sb(V) by thermal neutron activation analysis is proposed and applied to the study of the valence state of As and Sb in sea water. Immediately after sampling, As(III) and Sb(III) were separated from As(V) and Sb(V) by extracting their diethyldithiocarbamates with chloroform, and then back-extracted into diluted nitric acid. As(V) and Sb(V) in the aqueous phase were collected by thionalide cocrystallization. They were then irradiated for 30 min at a neutron flux of 2x1013 n/(cm2.s), and treated in the same manner as described in the previous report. The As and Sb were determined by gamma-ray spectrometry. Sea water has been found to contain 1.56 - 2.45 μg As/l and 0.37 - 0.60 μg Sb/l. 80 - 97% of arsenic and 70 - 94% of antimony existed as the pentavelent species, only 5 - 20% as the trivalent species, and the remainder was probably included in suspended matter. (auth.)