Direct injection of urine and determination of acetaminophen by micellar liquid chromatography with a wall-jet cell/carbon fibre microelectrode

A wall-jet cell/carbon fibre microelectrode detector was designed and used for the micellar liquid Chromatographie assay of acetaminophen. The separations were carried out in an analytical column packed with C18 stationary phase and the mobile phase was 0.05 mol 1−1 sodium dodecyl sulfate (SDS) containing 3% (v/v) n-propanol at pH 7.15. It is demonstrated that the oxidation current of acetaminophen can be enhanced by SDS micelles. The linear response range for acetaminophen was from 0.02 to 70 μg ml−1, with a detection limit of 0.02 μg ml−1 (signal-to-noise ratio = 2). Three urine samples were injected directly without time-consuming protein precipitation, and were analysed with a good recovery.