Arsine evolution-electrothermal atomic absorption method for the determination of nanogram levels of total arsenic in urine and water.

An arsine evolution-electrothermal atomic absorption method is described for the determination of ng/mL concentrations of total arsenic in urine and water. Organic-arsenic compounds are decomposed with nitric, sulfuric, and perchloric acids. Sodium borohydride, a redesigned hydride generator, and an electric-heated absorption tube are used for arsine evolution and its conversion to atomic arsenic. The method has a detection limit of 6 ng/mL, a sensitivity of 1 ng/mL, and is linear from 0 to 110 ng/mL of arsenic. Accuracy was established with two different National Bureau of Standards Standard Reference materials, and mean errors from 0 to -2 were obtained.