Growth rate estimation of βl-glutamic acid from online measurements of multidimensional particle size distributions and concentration

Abstract

A protocol for the estimation of growth kinetics for complex-shaped particles is presented. The estimation is based on multidimensional particle size distribution (nD PSD) and concentration data. While the latter is obtained by an in situ mid-infrared absorption probe, nD PSD data is measured via an imaging based setup presented earlier. The data is fitted to the output of a morphological population balance equation, which is solved by a customized high resolution algorithm. The procedure is first validated in silico using a virtual implementation of the measurement setup before it is applied to seeded desupersaturation experiments of the β polymorph of l-glutamic acid. Prominent broadening of the product PSD is observed and different size (in)dependent growth models are fitted to the data. Confidence intervals, local identifiability, and correlation of the parameters are studied. Finally, the estimated growth rate is compared to literature results. © 2013 American Chemical Society.