Direct chemiluminescence determination of ibuprofen by the enhancement of the KMnO₄-sulphite reaction

A simple, rapid, flow-injection chemiluminescence (CL) method is described for the determination of ibuprofen. A strong CL signal was detected when a mixture of the analyte and sulphite was injected into acidic KMnO₄. The CL signal is proportional to the concentration of ibuprofen in the range 0.1-10.0 mg/L. The detection limit is 0.02 mg/L ibuprofen, the relative standard deviation is 1.8% (0.5 mg/L ibuprofen; n = 11) and the sample measurement frequency is 120/h. The proposed method was successfully applied to the determination of ibuprofen in pharmaceutical preparations and in spiked urine samples. The mechanism of the CL reaction is also discussed.