An oxidative column for the flow injection analysis-spectrophotometric determination of paracetamol

A flow injection-spectrophotometric determination of paracetamol is reported. The procedure is based on the oxidation of the analyte with potassium hexacyanoferrate(III) previously retained in an anionic exchange column and the reaction of the N-(hydroxyphenyl)-p-benzoquinonimine so produced with phenol. The oxidation is carried out at room temperature and in aqueous ammoniacal solution. Concentrations of paracetamol in the 0.20-20 ppm range are determined with relative standard deviations (RSD) of 0.6% (n = 40) at an injection rate of 42 samples h-1. The influence of foreign species on the assay and its application to the determination of paracetamol in several pharmaceutical formulations are reported.