The GB/T 23372-2009 standard specifies a method for the determination of inorganic arsenic (arsenite As (II) and arsenate As (V)) in food by liquid chromatograph and Inductance Coupled Plasma Mass Spectrometry (LC-ICP-MS). This method is suitable for the quantitative analysis of inorganic arsenic in food, with a low detection limit: As (II) is 0.002 mg/kg, As (V) is 0.004 mg/kg. During the analysis process, after the inorganic arsenic in the sample has been extracted and purified, the different arsenic speciations are separated by liquid chromatograph, and determined by Inductance Coupled Plasma Mass Spectrometer (ICP-MS), which is combined with the standard sample for quantitative analysis. The reagent should be of excellent purity, and the water used should comply with the GB/T 6682-2008 standard.