One of the greatest challenges in oxidation research today is the determination ofin vivo oxidative stresses. In this investigation, the spectrofluorometry is used to monitor the kinetics of chloramine-T (CAT) oxidation of L-tryptophan (Trp) in basic solutions. The Trp-CAT reaction progress has been monitored at λmax = 485 nm (after using the excitation wavelength of 360 nm) over the temperature range, 293-313 K. The redox reaction follows a first-order dependence of the rate each on [CAT] and [Trp], and an inverse fractional-order on [OH-]. Variations of the ionic strength and the solvent dielectric constant have no effect on the rate. An addition of the reduction product of CAT, p-toluenesulfonamide, to the reaction mixture also has no influence on the rate. Based on the temperature effect, activation parameters are evaluated. A mechanism consistent with the observed kinetic and activation data has been proposed and the rate-law derived.
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