A New Reagent System for the Spectrophotometric Determination of Selenium in Environmental and Cosmetic Samples

S. O. S. in Chemistry, Pt. Ravishankar Shukla University, Raipur-492 010

Manuscript received 3 July 1997, accepted 1 August 1997

A new reagent system using leuco crystal violet (LCV) for the determination of selenium is described. The method is based on the reaction of selenium with acidified potassium iodide to liberate iodine which oxidizes LCV to form crystal violet having absorption maxima at 593 nm. Beer's law is obeyed over the concentration range 0.5-4.5 µg of Se in a final solution volume of 25 ml (0.02-0.18 ppm). The apparent molar absorptivity and Sandell's sensitivity were found to be 3.68 x 105 dm³ mol^-1cm^-1 and 0.0002 µg cm^-2 respectively. The method has been satisfactorily applied to the determination of selenium in a variety of environmental and cosmetic samples at ppm level. The method is highly sensitive, selective and convenient. Tellurium which interferes in most of the other methods does not interfere in this method.