DETECTION AND DETERMINATION OF SELENOPROTEINS BY NUCLEAR TECHNIQUES

Microbeam X-ray spectrometry, energy-dispersive X-ray fluorescence ana lysis, and neutron activation analysis were evaluated for the detectio n of selenium contained in the selenoprotein glutathione peroxidase. T he glutathione peroxidase had been previously separated using polyacry lamide gel electrophoresis. The use of Bragg-reflected polarized X-ray beams was employed in the X-ray fluorescence measurements to minimize the problem of scatter owing to the gel matrix. Current detection lim its of selenium in a gel matrix are 2.1 ng in the bench-top microbeam X-ray system and 30-60 ng using XRF with polarized beams. Neutron acti vation analysis was used for quality-control measurements, with a dete ction limit here of < 0.08 ng. The work has in principle established t he feasibility of such an approach.