HG-AFS Determination of Arsenic in Lycium Chinense with Microwave Assisted Sample Digestion

HG-AFS was applied to the determinations of arsenic in Lycium chinense. Sample was dissolved with HNO3 and H2O2, and hydride of As(Ⅲ) was generated from HCl(5+95) solution by reacting with 20.0 g·L-1 KBH4 solution. Flow-rates of 400 mL·min-1 for carrier gas and 1 000 mL·min-1 for shielding gas were taken in the analysis. Mixed solution of thiourea and ascorbic acid was added to the sample solution as pre-reductant. Linear relationship between the fluorescence intensity and mass concentration of As found was in the range of 0.05-10 μg·L-1, with detection limit (3S/N) of 0.032 μg·L-1. The proposed method was applied to the analysis of a CRM of spinach (GBW 10015), giving results in consistency with the certified values.