Determination of platinum derived from cisplatin in human tissues using electrospray ionization mass spectrometry.

Determination of platinum (Pt) derived from cisplatin in tissues was performed by electrospray ionization mass spectrometry (ESI-MS) using silver (Ag) as the internal standard. Pt and Ag reacted with diethyldithiocarbamate (DDC), and were extracted using isoamylalcohol and acidified with oxalic acid. The compounds were termed Pt(DDC)(3)(+) and Ag(DDC)(2)(+), based on their m/z values exhibiting the highest peaks at m/z 639 and m/z 405, respectively. The limit of detection was 30 pg and the quantitation range was from 100 to 10,000 pg using 5 mg tissue. The present method allowed the determination of Pt in wet-ashed tissue in 10 min.