Two-rate method for simultaneous kinetic determination based on detecting the final product in successive reactions Original Research Article

A simultaneous kinetic determination method based on detecting the final product in successive reactions is proposed. The method is carried out by measurement of the rate at two points during the course of the successive reactions and is, therefore, referred to as a two-rate method. The performance of the method is evaluated by successive reaction of epinephrine (EP) and norepinephrine (NE) with potassium hexacyanoferrate(III) [K3Fe(CN)6] for the determination of binary mixtures of the two catecholamines. Mixtures of the two catecholamines (>2×10−5 mol l−1 each) with different ratio are resolved within a relative error of <5% while other data processing methods fail to give reliable results. The method can increase sensitivity and overcome baseline drifts in flowing systems. The reason why the two-rate method based on successive reactions works well is explained by the kinetic curve simulation studies.