Determination of trace amounts of total arsenic in environmental samples by hydride generation flow injection-AAS using a mixed acid as a pretreatment agent

A method is described for the determination of total arsenic by hydride gen eration-atomic absorption spectrophotometry using a mixed acid as a pretrea tment. Hydride generation is done by the flow-injection method. The authors investigated in detail the temperature and time of decomposition using ino rganic, organic arsenic and environmental standard samples, pretreated with nitric-perchloric-sulfuric mixed acid. By using a mixed acid as a pretreat ment agent at 220 degreesC, the decomposition time could be shortened and t he blank value of arsenic from the reagents used was reduced. The mixed aci d of nitric-perchloric-sulfuric was also found to be effective as a pretrea tment agent for organic arsenic compounds in which a dimethylated compound, sodium cacodylate or biological samples, is known to be one of the indecom posables. The present approach was proved to be satisfactory as a pretreatm ent for the quantitative analysis of trace amounts of total arsenic in liqu id or solid environmental samples, such as geothermal water, sediments and biological samples.