Comparative study on ATR-FTIR calibration models for monitoring solution concentration in cooling crystallization

Abstract

Abstract:In this paper calibration model building based on using an ATR-FTIR spectroscopy is investigated for in-situ measurement of the solution concentration during a cooling crystallization process. The cooling crystallization of L-glutamic Acid (LGA) as a case is studied here. It was found that using the metastable zone (MSZ) data for model calibration can contribute to the prediction accuracy, compared to the usage of undersaturated zone (USZ) spectra as traditionally practiced which may lead to undesired bias for prediction of the MSZ concentration. Calibration experiments were made for LGA solution under different concentrations. Four candidate calibration models were established using different zone data for comparison, based on a multivariate partial least-squares (PLS) regression algorithm for the collected spectra together with the corresponding temperature values. Experiments under varied concentrations and operational changes of temperature were conducted. The results indicate that using MSZ spectra for model calibration can give more accurate prediction of the solution concentration during the crystallization process. The primary reason was clarified as spectral nonlinearity for measurement between USZ and MSZ. In addition, an LGA cooling crystallization experiment was performed to verify the sensitivity of these calibration models for monitoring the crystal growth process.

Interplay between Thermodynamics and Kinetics on Polymorphic Behavior of Vortioxetine Hydrobromide in Reactive Crystallization

“…To investigate the RC process and to determine the effect of reaction and crystallization on polymorphic formation, the RC process of VH in the four solvents at 313.15 K was online monitored by ATR-FTIR. − The initial supersaturation of form B was controlled at around 5.60. During the process, the absorption spectra of the reaction solution were collected with 1 min intervals.…”

Estimation of Kinetics for Batch Cooling Crystallization by Focused‐Beam Reflectance Measurements

“…Concentration was measured by FT‐IR‐ATR (Mettler‐Toledo, React‐IR model 45m). Concentration can be determined from FT‐IR‐ATR peak intensity and temperature , . Measurement conditions and calibration method of FT‐IR‐ATR are listed in Tab.…”

Parameter Estimation of the Stochastic Primary Nucleation Kinetics by Stochastic Integrals Using Focused-Beam Reflectance Measurements

“…The IR spectrum was measured with Fourier transform infrared-attenuated total reflection spectroscopy (FT-IR-ATR, made by Mettler Toledo International Inc., Columbus, OH, USA) and was utilized for obtaining the Arg concentration. The peak intensity of the FT-IR-ATR has been reported to be affected by the solution temperature [28,29]. The calibration equation used in this study is represented as follows:…”