Abstract: Flash frozen plasma samples were thawed and ultrafiltered at 4000 g for 30 min using filters with a 10 000 mol. wt. cut off. The ultrafiltrate was stored at -25°C before use. Portions (20 or 50 µL) were analyzed on an anion-exchange 5 µm Nucleosil SB column (7 cm x 3.2 mm i.d. or 15 cm x 4.6 mm i.d.) for cisplatin and on a cation-exchange 5 µm Nucleosil SA column (15 cm x 3.2 mm i.d.) for the monohydrated complex, with 0.125 M succinic acid of pH 5.2/methanol (2:3) as mobile phase (0.5 ml/min). Post-column reaction was performed using a packed bed reactor steel column (50 cm x 0.35 cm i.d.) of glass beads (details given), operated at 115°C with a mobile phase (0.17 ml/min) of sodium diethyldithiocarbamate in aqueous methanol. Detection was at 344 nm. The RSD of the determination was 11.5% for 20 ng of the monohydrate and 8% for 9 ng of cisplatin.