DETERMINATION OF SELENIUM SPECIES IN SEAWATER BY FLOW-INJECTION HYDRIDE GENERATION IN-SITU TRAPPING FOLLOWED BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY
Jy. Cabon et W. Erler, DETERMINATION OF SELENIUM SPECIES IN SEAWATER BY FLOW-INJECTION HYDRIDE GENERATION IN-SITU TRAPPING FOLLOWED BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY, Analyst (London. 1877. Print), 123(7), 1998, pp. 1565-1569
In this study, Se-IV was determined in seawater by flow injection hydr
ide generation, trapping within the graphite furnace, followed by elec
trothermal atomic absorption spectrometry. The optimized protocol perm
itted a preconcentration factor of 1000 lowering the detection limit o
f Se-IV in seawater to about 1.5 ng l(-1) for a 25 mi sample volume, B
ecause this technique is specific to Se-IV, various physico-chemical t
reatments leading to the conversion of other chemical forms into Se-IV
were investigated. Thermal and UV irradiation treatments of seawater
samples in acidic or basic medium permitted the conversion of Se-II-se
lenomethionine and Se-VI to Se-IV. Based on the different responses of
selenium species towards the photochemical treatments, an operational
speciation model of selenium species in seawater is proposed. Accordi
ng to our analytical protocol, 21 ng l(-1) Se-VI, 10 ng l(-1) Se-IV an
d 13 ng l(-1) organic Se-II species mere determined in a coastal surfa
ce seawater collected near Brest.