Chemiluminescence detection of porphyrins with the peroxyoxalate reaction by flow-injection analysis

The Chemiluminescence (CL) reaction of bis(2,4-dinitrophenyl) and bis(2,4,6-trichlorophenyl)oxalate with hydrogen peroxide was employed for the study of CL-emission characteristics from porphyrins. The effects of experimental factors such as pH, solvents, flow rate, and reagent concentrations on CL kinetics and intensity were investigated. Based on these studies, a new method involving the coupling of CL with flow injection analysis (FIA) was developed for the rapid screening of porphyrin(s) present in a real simple matrix, with good sensitivity, selectivity and precision. Under optimized conditions, the detection limit for urinary coproporphyrin was about 0.1 μg 1−1 (SN = 3) and the average precision was about 1.5% (rsd). Perhaps, most importantly, significant enhancement in the selectivity was demonstrated for the CL detection of coproporphyrin against common urinary metabolites, such as riboflavin and bilirubin, when compared with fluoresence detection.