Determination of inorganic and organic selenium species in natural waters by cathodic stripping voltammetry

The determination of the total concentration of a trace element gives only few informations about its toxicity and its bioavailability which depend mainly on the different chemical forms under which it is present. The studies of the chemical speciation is thus particularly important. We propose, in this paper, a selenium speciation model for the studies of natural waters based on Se(IV) voltammetric determination. The separation of the organic and inorganic forms was realized by a rapid ion exchange method and total selenium was determined after a u.v. irradiation.