Speciation of platinum metabolites in plants by size-exclusion chromatography and inductively coupled plasma mass spectrometry

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.