Abstract

This paper analyses several mathematical approaches for simultaneous determination of dibucaine (D) and chlorphenamine maleate (CM). The different calibration methods utilised were: first derivative spectrophotometry (FDS), classical least squares (CLS), regression of partial least squares (PLS), and principal components regression (PCR). For the multivariated methods, the limits of detection (LOD) for multivariate calibrations were determined creating a surrogate signal variable (SSV). The recoveries were selected to confirm the validity of the models. In general, the CLS model presents the poorest recovery. In order to compare the exactitude of the different calibration methods, a one-way ANOVA test was performed. In these analyses, only the CLS calibration method produced a significantly different prediction. The lowest LODs were achieved by CLS and FDS, although the former method presented lower precision and poor prediction. Therefore, the FDS method is proposed as a pure binary calibration method for D-CM mixed samples, including the prepared according to a medical prescription and plasma samples simulating an event of intoxication.