A KINETIC-STUDY OF THE OXIDATION REACTION OF L-CYSTEINE BY POTASSIUM HEXACYANOFERRATE(III) IN AQUEOUS ACIDIC MEDIUM

Kinetics of oxidation of L-cysteine by one-electron oxidant, potassium hexacyanoferrate(III) have been investigated spectrophotometrically a t 420 nm as a function of temperature, pH and ionic strength, The rate data indicate first order dependence each in [Fe(CN)(6)(3-)] and [CyS ]. The reactive species of cysteine are neutral cysteine and protonate d cysteine, The effect of ionic strength on the reaction has little ef fect, The activation parameters Delta H and Delta S* have also been c alculated. The results support for an associative mechanism for the re action.