[Determination of total arsenic and mercury in the fucoidans by hydride generation atomic fluorescence spectroscopy].

In the present article, the method of high pressure microwave digestion and hydride generation atomic fluorescence spectroscopy (HG-AFS) was used for the determination of total arsenic and mercury in fucoidans, and the detecting conditions were optimized, including instrument working parameters, such as atomic temperature, lamp current, high voltage of PMT etc, and the conditions of hydride generation, such as the acid concentration of loading fluid, speed of carrying gas, the concentration of KBH4 etc. The result shows that there are good linear relations between fluorescence intensity and the concentrations of arsenic and mercury where their concentrations are 0-200 microg x L(-1) and 2.0-10.0 microg x L(-1), respectively, and the related coefficient of arsenic is 0. 999 9 and that of mercury's is 0. 999 8. The blanks of samples were detected constantly (n = 10), and the detection limit of this method is 0.173 ng x kg(-1) for total arsenic and 0.012 2 ng x kg(-1) for mercury. In order to do precise analysis, the samples were detected constantly (n = 8), and the relative standard deviations (RSDs) of arsenic and mercury are 1.09% and 1.69%, severally. The quantitative arsenic and mercury were added into the samples before they were digested, and the recovery range is 93.31%-100.9% for arsenic and 91.21%-106.1% for mercury. The contents of total arsenic and mercury in fucoidans before desalted by ultrafiltration are 2.78 mg and 0.125 mg x kg(-1), respectively. Nevertheless, the contents of total arsenic and mercury in fucoidans desalted by ultrafiltration are 2.26 mg x kg(-1) and 0.119 mg x kg(-1), severally.