Evaluation of a modified derivative method for spectrophotometric and spectrofluorimetric kinetic-based determinations

Abstract

A selective empirical data processing method based on a modification of the conventional kinetic derivative method is reported. The method is based on parameters not directly correlated with the initial rate but which are similar to those used in derivative spectrometry such as the distance between two peaks or the value of the derivative at a single time. Two types of kinetic curves were tested, namely, curves with and without induction periods. Different order derivatives were obtained by numerical differentiation using the Savitzky-Golay method. Measured parameters were evaluated for each derivative curve in terms of linearity for the analyte of interest and selectivity with respect to an interferent, and compared with those obtained by using initial-rate measurements. The proposed method is shown to provide improved selectivity.