Investigation of low molecular weight platinum species in grass

The analysis of the low molecular weight fraction (<10 kDa) of platinum species in grass is described. This fraction is isolated by ultrafiltration, gel-chromatography and preparative isotachophoresis and then further separated by liquid chromatography with diode-array UV and pulsed amperometric detection. Platinum is determined in eluted fractions by using a very sensitive adsorptive voltammetric method. The strong correlation of platinum concentration with the highly selective pulsed amperometric detection enables the platinum binding ligands to be identified as carbohydrate-oligomers (MW about 1 kDa). Further evidence of this result is obtained by using capillary electrophoresis as an independent separation technique.