Determination of Trace Selenium in Biological Samples by Inductively Coupled Plasma-Mass Spectrometry with Microwave Digestion

Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS) with wet digestion is classical method to determine the trace element selenium in biological samples. The analytical requirements cannot be met by low resolution HG-AFS and wet digestion processing and carries the additional disadvantages of high quantities of reagent consumption, lengthy processing time and production of high background values. Accelerating digestion processing time and reducing the amount of reagent consumption have been considered as prerequisites for increasing detection limit and resolution of selenium. In this article, samples were analyzed by HG-AFS and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) after two different sample pretreatments of wet digestion and microwave digestion. The method of ICP-MS with microwave digestion was established through these contrast tests. The results indicate that microwave digestion can reduce digestion time, decrease reagent consumption and lower background in high-pressure sealed conditions. Detection limits of HG-AFS and ICP-MS are 0.03 μg/g and 0.01 μg/g, respectively. In addition, according to the determination for national standard reference samples, relative standard deviations of HG-AFS and ICP-MS are less than 10% and 4%, respectively. Obviously, low detection limits and improved accuracy and precision can been acquired by direct analysis with ICP-MS. The established method is simple to operate and can been conducted for the rapid determination of trace selenium in various biological samples.