A transition metal enhanced luminol chemiluminescence in the presence of achelator

We have investigated the chemiluminescence signal of luminol and hydrogen p eroxide in the presence of a transition metal (Co(II), Cu(I), Fe(II), Fe(II I)) and of a chelator (EDTA, citric acid) in pH 8.5, 9 and 10 berate buffer solutions. We observed that the chemiluminescence intensities of these sys tems reached a plateau, where they remained stable for a period of 2-30 s. We also observed linearity between the intensity of chemiluminescence and t he hydrogen peroxide concentration. The combination of Co(II) and EDTA at p H 9 was found to give the optimum signal with reference to time stability, intensity and reproducibility. Thus, compared to previous chemiluminescence applications, the present results permit us to propose a simple, enzyme-fr ee and time-independent technique for the detection and quantification of h ydrogen peroxide. (C) 2001 Elsevier Science Inc. All rights reserved.