Both sets of samples generated by precipitating bovine plasma with acetonitrile (1:4, v/v). Centrifugation performed at 3000 rpm for 5 minutes. HPLC gradient: 10% acetonitrile (0.5 min), ramp to 60% acetonitrile (0.5 min), hold for 2 min, ramp to 10% acetonitrile (0.5 min). HPLC column: Polaris C18-A, 3 μm, 2 x 50 mm. Injection volume - 100 μL.
