Determination of paracetamol (acetaminophen) in blood and plasma using high performance liquid chromatography with dual electrode coulometric quantification in the redox mode.

A simple, but sensitive, micro-assay for paracetamol in blood and plasma is described. Samples were prepared by precipitation with trichloroacetic assay solution and the drug quantified by reversed phase liquid chromatography with dual electrode electrochemical detection in the redox mode (oxidation at +0.25 V followed by reduction at -0.15 V). The limit of detection was 0.1 mg/L for a 10 microL sample of blood or plasma, the coefficient of variation at this concentration being 11.4%. The method was applied to a study of gastric emptying in patients before and after cardiac surgery.