Systematische Fehler bei der Selenbestimmung im ng/g-Bereich in biologischen Matrices nach dem Hydrid-AAS-Verfahren

Summary Four biological standard-reference materials (NBS and IAEA) were mineralized with two independent decomposition methods — a wet decomposition with a mixture of HNO₃/HClO₃/HClO₄ using an optimized temperature-time programme, and a combustion method in an oxygen stream (Trace-O-Mat). The selenium contents of the decomposition solutions were determined by the hydride-AAS method. The selenium concentrations were in agreement with the certified values at low sample weights, but decreased as the sample weights were increased. This effect is independent of the decomposition method, but is caused by interferences of concomitant elements in the μg/g-range with the formation of selenium hydride, as has been previously discussed [3].