Flow injection–electrothermal atomic absorption spectrometry for arsenic speciation using the Fleitmann reaction

Abstract

A hybrid procedure was developed for the selective determination of inorganic As species, based on the generation of arsine in a flow injection system by the Fleitmann reaction with its subsequent trapping in a graphite furnace coated with microgram amounts of possible absorbers. Efficient trapping of the arsine was achieved on Pd at 200 °C, although other elements, such as Ru, Ce, Ag and Pt, can also be used to sequestrate the hydride, but with lower sensitivity. Optimization of the experimental parameters affecting the generation and trapping of the arsine and the arsenic atomization resulted in improved sensitivity, which allowed an absolute detection limit of 10 pg of As. The recommended method was satisfactorily applied to the determination of inorganic As species in various types of water samples and of total As in a variety of certified reference materials.