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A combined procedure was developed for the determination of As and Bi in biological materials by total reflection X-ray fluorescence (TXRF). The materials were first digested by an open wet decomposition method. The separation of both elements from the sample matrix was then achieved by generation of their volatile hydrides and subsequent trapping in a collection solution. The quantitative determination of As and Bi was performed simultaneously by TXRF using Y as internal standard. The procedure was applied to several different biological certified reference materials. The recovery rate determined for mass fractions between 40 ng g–1 and 10 µg g–1 was 90–100% after correction with aqueous standard solutions. The RSD for the whole procedure ranged from 8 to 14% and the detection limits were about 10 ng g–1 for As and 20 ng g–1 for Bi.

The multi-element capability of ICP-MS was exploited in a study of platinum metabolization in plants. Grass was cultivated with and without treatment with a Pt containing solution. Platinum species were extracted and separated by ultrafiltration into two mass fractions. The low molecular mass (<10 kDa) fraction was investigated by size-exclusion chromatography coupled on-line to ICP-MS. Five Pt containing fractions could be distinguished in the chromatograms. Conclusions on the binding partners of Pt could be drawn from multi-element determinations of some selected elements (C, S, Ca, Pb) that are co-eluted with Pt. For two of them (S, Ca), the higher mass resolution available with a double focusing magnetic field ICP-MS instrument was applied in order to cope with problems from spectroscopic interferences.