Studies are presented describing direct, clog-free productlon of hlgh density flnely dlspersed aerosols from highly complex samples through use of a speclai nebulizer design based on principles first developed by R. S. Babington. Appllcatlon of thls technlque to sample lntroductlon for atomic absorption spectrometry is described for matrices of combined hlgh suspended solids content, Increased vlscoslty, and elevated salt concentration. Cu and Zn are determined In whole blood, urine, seawater, evaporated milk concentrate, and tomato sauce with mlnimal sample preparation.

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When tested individually In a clean system, NOa~a nd HNOa are shown not to be serious Inhibitors of AsH3 and H2Se evolution. The real inhibitors of AsH3 and H2Se evolution (encountered when solid samples are oxidatively dissolved In nitric acid) are shown to be correspondingly reduced nitrogen oxides (N02~, etc.) produced In sample digestion. Volatile NO, Interferants can then result upon acidic disproportionation. These volatile NO, species are found to transport with the AsH3 and H2Se analyte. The N203 species Is detected In a cryogenic trap. When dissolved In downstream H2S04 drying agents, the NO, can give rise to powerful oxidants such as NO+ which can accumulate In the H2S04 and thereby account for "memory Interferences" encountered with subsequent samples. The use of sulfamic acid Is Investigated In the preliminary removal of reduced nitrogen oxides such as N02~. Transition metal cation interferences are also studied. Several metal masking procedures previously reported to work well for AsH3 are shown here to fall for the evolution of H2Se. BH3CN" Is shown to be an effective new reductant to evolve AsH3 and H2Se from As(III,V) and Se(IV) In acid media.

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