Determination of arsenic in soil and plant materials by atomic-absorption spectrophotometry with electrothermal atomisation

Abstract

A method is described for the determination of arsenic in soil and plant materials by hydride generation and atomic-absorption spectrophotometry using electrothermal atomisation. Soils are decomposed by leaching with a mixture of nitric and sulphuric acids or fusion with pyrosulphate, and plants by wet oxidation with nitric and sulphuric acids. The resultant acidic sample solution is made to react with sodium borohydride and the liberated arsenic hydride is swept into an electrically heated tube mounted on the optical axis of a simple, laboratory constructed atomic-absorption apparatus.

The advantages of high sensitivity, rapid analysis and simplicity of equipment are discussed, and the results for both types of sample material are compared with values obtained by use of the molybdenum-blue method.