Simultaneous Determination of Trace Arsenic and Mercury in Geological Samples by Hydride Generation-Atomic Fluorescence Spectrometry with Water Bath Soaking Sample Preparation

Geological sample was digested with mixed acid (V_HCl∶V_HNO3∶V_H2O=3∶1∶4) in water bath and then the mixed solution of thiourea and ascorbic acid as the reductant was directly added in the sample solution. The arsenic and mercury in the sample solution were determined simultaneously by hydride generation-atomic fluorescence spectrometry. The detection limits of the method for arsenic and mercury were 0.0336 ng/mL and 0.0037 ng/mL, respectively. The reliability of the method was tested by determination of arsenic and mercury in National Standard Reference materials of GBW 07109~07114, GBW 07301~07312, GBW 07401~07408. The results were in agreement with the certified values with precision of 1.1%RSD for As and 3.0%RSD for Hg.