Synergistic effect of Chromotrope 2R as a novel sensitizer for chemiluminescence reactions of potassium permanganate: Determination of naproxen and naltrexone

A novel chemiluminescence (CL) reaction was proposed to determine naproxen and naltrexone based on the synergistic effect of Chromotrope 2R in the CL system of acidic KMnO4. Eight dyes including Chromotrope 2R, Rhodamine 6G, Amido black 10B, Eosin Y, Amaranth, Brilliant blue, Orange G and Victoria blue were evaluated, and Chromotrope 2R produced the highest signal and signal to background for the analytes, namely ascorbic acid, citric acid, oxalic acid, tartaric acid, maleic acid, thiourea, codeine, pholcodine, naproxen and naltrexone. Among these species, naproxen and naltrexone were chosen as model analytes. In the proposed method, the weak CL intensity of acidic KMnO4-naoproxen (or other analytes) increased significantly in the presence of Chromotrope 2R, and the CL intensity was proportional to napmxen (or naltrexone) concentration. The CL reaction mechanism was investigated through UV-Vis, fluorescence and CL spectra. Under optimal conditions, the CL intensity was found to be linearly proportional with the naproxen and naltrexone concentrations respectively in the range of 23-4600 mu g mL(-1) and 1.3-238.7 mu g mL(-1). The limits of detection for naproxen and naltrexone were 4.7 and 0.1 mu g mL(-1), respectively. The relative standard deviation (n = 7) for 161.2 mu g mL(-1) naproxen and 13.6 mu g mL(-1) naltrexone was 4.8% and 5.9%, respectively. This method was used for determination of naproxen in drug formulations and naltrexone in synthetic samples.