Chemiluminescence detection of paracetamol by a luminol-permanganate based reaction

The flow injection analysis of paracetamol was developed based on its inhibitory effect on a luminol-permanganate chemiluminescence system. With a system containing solutions of 2.5mM luminol, 5.0µM KMnO4 and pH 12.0 phosphate buffer (K2HPO4/NaOH), a detection limit of 1.0×10-8M (1.5ppb) and a linear dynamic range of 2.5×10-8 to 2.5×10-7M can be obtained. A repetitive injection of 1.0×10-7M paracetamol solutions gave satisfactory reproducibility with a relative standard deviation of 2.3% (n=12). Possible interferences from major excipients in pharmaceuticals and other related compounds were also studied. Contents of paracetamol in two locally available pharmaceuticals were analyzed. From the recovery of 98.2-104.4% obtained, the feasibility of the developed method for real sample analysis was confirmed.