Calibration transfer in model based analysis of second order consecutive reactions

Abstract

In the present work, UV–VIS spectroscopic data from a second order consecutive reaction between ortho-amino benzoeic acid (o-ABA) and diazonium ions (DIAZO) with one intermediate was studied. Since o-ABA was not absorbing species in visible region of interest the closure rank deficiency problem did not exist. Analysis of simulated and experimental data shows that in the presence of variations between spectra of pure species in different data matrices, applying the model based methods to augmented datasets leads to inaccurate results. The application of a calibration transfer method as an additional step in the hard modeling procedure improves the precision of results, and accurate estimation of reaction rate constants is obtained. Effect of different types of spectral variations including intensity, shift or broadening is tested in simulated data. The proposed method is compared to local spectra mode of analysis (LSMA) which is proposed by Puxty et al. A comparison of the results shows that the proposed method is more efficient than LSMA and leads to less uncertainty in estimated rate constants and less percent error in the relative residuals.