The methods studied were: basic digestion with tetramethylamonium hydroxide (TMAH) 25% (v/v), acid digestion with hydrochloric acid 3% (v/v), and direct acid digestion with modifier Triton X-100 0.6% (v/v). A 500 _L volume of mice pooled plasma was spiked with varied volumes of Pt standard solution directly in the autosampler vial. The basic digestion was performed by adding 200 _L of TMAH 25% (v/v) and the acid digestion with 60 _L of hydrochloric acid (3%, v/v final concentration)