Speciations of Soluble Arsenic and the Limit Standard in Alismatis Rhizome, Lonicerae Japonicae Flos and Spatholobi Caulis by HPLC-ICP-MS

OBJECTIVE To establish a method for determination of the soluble arsenic in Alismatis Rhizome, Lonicerae Japonicae Flos and Spatholobi Caulis by HPLC-ICP-MS. To evaluate the residual of soluble arsenic and provide the basis for the formulation of soluble arsenic residues. METHODS The samples were extracted by 0.05 mol·L^-1 EDTA with ultrasonic treatment, then detected by HPLC-ICP-MS. RESULTS Concentration of As(Ⅲ) , DMA, MMA and As(Ⅴ) in the range of 5-200 μg·L^-1 showed good linear relationship, the average recovery (n=9) were in 108.4%-105.1%, and the detection limit of the method was 0.01 mg·kg^-1. Small amounts of As (Ⅲ), As (Ⅴ) were detected in Alismatis Rhizome. Small amounts of As (Ⅲ), DMA, As (Ⅴ) were detected in Lonicerae japonicae flos. None was detected in Spatholobi Caulis. CONCLUSION The method is simple, accurate, and reproducible, it can be used for analysing the residual limit of As(Ⅲ) , DMA, MMA and As(Ⅴ).