Determination of Trace Arsenic Using Microwave Digestion/Hydride Generation/Graphite Furnace Atomic Absorption Spectrometry

All arsenic species in groundwater were firstly oxidized into As (Ⅴ) form by using nitric acid and perchloric acid under microwave irradiation. As (Ⅴ) was then reduced into As (Ⅲ) by sulfourea and ascorbic acid. Taking sodium borohydride as reducing agent,the trace arsenic in the sample was determined by hydride generation/graphite furnace atomic absorption spectrometry. The experimental conditions for the quantitative analysis of arsenic including carrier gas flow rate,pyrolysis temperature and so on were investigated. The limit of detection for arsenic is 0.12 μg/L,the recovery rates with standard addition are 95.5% to 102.6%,and the relative standard deviation is 2.6% to 3.5% in sample determination was achieved. The method is suitable for analysis of trace arsenic in groundwater.