Speciation of inorganic selenium and selenoamino acids by an HPLC-UV-HG-AFS system

For the on-line speciation of selenocystine (SeCys), selenomethionine (SeMet), selenoethionine (SeEt), selenite (Se(IV)) and selenate (Se(VI)), a high-performance liquid chromatography-UV irradiation-hydride generation-atomic fluorescence spectrometric method is described. Separation was carried out on a conventional reversed-phase C18 column modified with didodecyl-dimethylammonium bromide with gradient elation applying two concentrations of amonium acetate as the mobile phase. UV irradiation and hydride generation parameters were optimized, The obtained detection limits for SeCys, SeMet. SeEt, Se(IV) and Se(VI) were 0.31. 0.43, 0.7, 0.44 and 0.32 ng ml(-1), respectively using a 100-mul loop. The method was tested with spiked mineral water and two volunteers' urine samples.