Ultrasound Accelerated Solid-Liquid Extraction for the Determination of Selenium in Biological Samples by Electrothermal Atomization Atomic Absorption Spectrometry

A novel method for sample preparation by ultrasound-accelerated solid-liquid extraction prior to selenium determination in the phosphate-rich biological samples by electrothermal atomization atomic absorption spectrometry (ETAAS) with continuum-source background correction and nickel nitrate as a chemical modifier was established and compared with the results of conventional sample wet decomposition (however, this last item was not the object of this study). Diluted (4%) nitric acid was used as an extraction medium. The evaluation of the analytical results for biological Certified Reference Materials indicates that the results of a selenium determination after wet acid digestion (HNO3+HCl+H2O2) agreed well with the certified values, whereas the proposed solid-liquid extraction procedure can be used for simple and rapid control of the selenium levels.