Speciation Analysis of Arsenic in Soil Samples

A new method for analysis of four arsenic species of As(Ⅲ)， As(Ⅴ)， methanearsonic acid (MAA) and dimethyl arsenic acid (DMA) in soil samples was developed. Phosphoric acid was chosen as the extractant and two techniques of ultrasonic wave and water bath were used for extracting the arsenic species from soil samples. Ion chromatographyhydride generationatomic fluorescence spectrometry was used for the determination of arsenic species. The recovery of the method was 72.0%～105.4% with precision of 2.61%～8.19%RSD(n=5).The analytical results from the study showed that the extraction efficiency by water bath was remarkably superior to that by ultrasonic wave. And the results also showed that the main arsenic species in soils were inorganic arsenic such as arsenate and arsenite, in which As(Ⅴ) was in abundant and no organic arsenic was detected. 