Fluorometric Determination of ppt Level Selenium (IV) in Sea Water by a Coprecipitation Method with Zirconium Hydroxide

Abstract

Selenium (IV) was coprecipitated with zirconium (IV) hydroxide formed at pH 7.5 in 1,000ml of seawater, whereas selenium (VI) was not coprecipitated. After centrifuging the precipitate, it was dissolvedwith hydrochloric acid. In the presence of zirconium (IV), trace selenium (IV) was extracted with 2, 3-diaminonaphthalene into cyclohexane, and was fluorometrically determined. This coprecipitation methodwas rapid, convenient, highly sensitive and free from contamination, since it was carried out in a subclosedsystem (using one beaker and one centrifugal tube) and a zirconium reagent containing negligible amounts of selenium was used.