A. Varadarajan et al., Extractive spectraphotometric determination of selenium traces with bis(ethanedithioamido)-2,4-dioxo-3-oxyminopentane, CHEM ANAL, 44(6), 1999, pp. 1075-1084
Bis(ethanedithioamido)-2,4-dioxo-3-oxyminopentane (bis(EDA)DOP) is proposed
as a new sensitive and selective reagent for the spectrophotometric determ
ination of selenium traces. The method is based on the color reaction betwe
en selenium(IV) and his(EDA)DOP on heating the mixture at 50 degrees C for
2.0 min, which is extractable in l-octanol from an aqueous medium acidic wi
th respect to 2--3 mol l(-1) HCl on shaking for 1.5 min. The absorbance of
the extracted species is measured at 495.0 nm and the molar absorptivity is
1.268 x 10(4) l mol(-1) cm(-1). The complex system obeys Beer's law within
0.2-15.0 mg ml(-1) in Ringbom's optimum working range of 4.36-12.02 mu g m
l(-1) with a sensitivity of 2.21 ng cm(-2) for effective spectrophotometric
determination of total selenium. The nature of the extracted species is ML
2 as derived by the mole ratio and slope ratio methods. The method is satis
factorily applicable to the determination of total selenium in various synt
hetic mixtures and other samples.