Precipitation of alpha L-glutamic acid: determination of growth kinetics.

Growth kinetics of alpha L-glutamic acid was determined based on seeded batch desupersaturation experiments. The growth rate correlation applied in this study accurately describes the growth process in a temperature range of 25-45 degrees C and in a supersaturation range of 1-3. The newly developed approach for the growth rate characterization has the advantage of a high robustness especially with respect to the influence of competing particle formation mechanisms as nucleation or agglomeration. The efficient technique employs in situ process analytical technologies, e.g. attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and focused beam reflectance measurement (FBRM), different ex situ analytical tools and population balance modeling combined with a non-linear least squares optimization algorithm to determine the growth kinetics. The growth mechanism was identified to be integration controlled and of birth and spread (B + S) type. The quality of the determined growth rate correlation was assessed by comparison with the experimental data and with literature data.