The quenching effect of glutathione, L-cysteine, and L-methionine on the strong chemiluminescence (CL) intensity of bis(2,4,6-trichlorophenyl)oxalate (TCPO)–H2O2 in the presence of rubrene (5,6,11,12-tetraphenylnaphthacene) as a fluorescer was investigated. Kinetic parameters for the peroxyoxalate chemiluminescence (PO–CL) including the intensity at maximum CL, time at maximum intensity, total light yield, theoretical maximum level of intensity and pseudo-first order rate constants for the rise and fall of the CL burst (kr and kf) were also calculated using the pooled intermediate model by a computerized non-linear leastsquares curve fitting program (KINFIT). These systems resulted in Stern–Volmer plots in the quencher concentration range of 2.5 9 10-5 to 2.25 9 10-4 M, with kQ values of 2.5 9 104, 2.1 9 104 and 1.1 9 104 M-1, for glutathione, L-cysteine, and L-metionine, in order.
