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

A simultaneous kinetic determination method based on detecting the final pr oduct in successive reactions is proposed. The method is carried out by mea surement of the rate at two points during the course of the successive reac tions and is, therefore, referred to as a two-rate method. The performance of the method is evaluated by successive reaction of epinephrine (EP) and n orepinephrine (NE) with potassium hexacyanoferrate(IH) [K3Fe(CN)(6)] for th e determination of binary mixtures of the two catecholamines. Mixtures of t he two catecholamines (>2 x 10(-5) Mol l(-1) each) with different ratio are resolved within a relative error of <5% while other data processing method s fail to give reliable results. The method can increase sensitivity and ov ercome baseline drifts in flowing systems. The reason why the two-rate meth od based on successive reactions works well is explained by the kinetic cur ve simulation studies. (C) 2001 Elsevier Science B.V. All rights reserved.