USE OF A SURFACTANT IN THE DETERMINATION OF ARSENIC BY FLOW-INJECTIONHYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY

The possible benefits of the addition of an anionic surfactant, didode cyldimethylammonium bromide, in the determination of arsenic, by flow injection hydride generation atomic absorption spectrometry using a fl ame-heated quartz tube atomizer, were studied in the light of previous reports concerning the effects of surfactants on chemical vapor gener ation procedures. Concentrations of arsenic between 5 and 30 mu g l(-1 ) were used. Calibrations in the presence and absence of the surfactan t in the sample solution were not significantly different, either for the case where vesicles were formed in the presence of the analyte or where they were preformed in the surfactant solution and then added to the analyte. The surfactant had no effect on recoveries in the presen ce of copper, nickel or bismuth. The addition of the surfactant to the acid carrier and/or borohydride streams had no effect. It is proposed that there may be a greater role for surfactants in the improvement o f the processes by which the hydride is transferred to the bulk gas ph ase than has been attributed in previous reports on this subject.