Determination of selenium in the human brain by graphite furnace atomic absorption spectrometry

For the investigation of neurological disorders, a development of simple and accessible methods for determining selenium in human brain samples is required. We devised a method of determining selenium using graphite furnace atomic absorption spectrometry (GFAAS). An electrodeless discharge lamp provided the sufficient sensitivity to determine brain selenium. The matrix interferences were avoided by using high temperature, a prolonged pyrolysis step, and a palladium matrix modifier. The technique of standard addition was used to evaluate the sample concentrations. The accuracy of the method was confirmed by a bovine liver reference material. The detection limit of selenium was 0.04 ng. The determined selenium concentrations of human brain cortex and white matter were higher than those of putamen (115-155 and 206-222 ng/g wet wt, respectively). These GFAAS values agreed with those obtained by fluorometric analysis (r = 0.91, n = 10). Moreover, the GFAAS values were compatible to those reported by other researchers (99-274 ng/g wet wt), in which selenium concentrations in putamen also tended to be higher than the other two regions. We conclude that GFAAS is useful for selenium analysis in brain samples.