Simultaneous characterization of multiple properties of solid and liquid phases in crystallization processes using NIR

作     者：Chao Y. Ma Xue Z. Wang 

作者机构：Institute of Particle Science and Engineering School of Process Environmental and Materials Engineering University of Leeds Leeds LS2 9JT UK 

出 版 物：《Particuology》 (颗粒学报（英文版）)

年 卷 期：2011年第9卷第6期

页      面：589-597页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 0817[工学-化学工程与技术] 08[工学] 080203[工学-机械设计及理论] 070302[理学-分析化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0802[工学-机械工程] 0702[理学-物理学] 

基　　金：UK Engineering and Physical Sciences Research Council for funding the research (EPSRCGrant Reference: EP/C001788/1) 

主　　题：Process analytical technology Near infrared spectroscopy Support vector machine Genetic algorithm Wavelength selection Cooling crystallization 

摘      要：Near infrared spectroscopy （NIR） is now probably the most popular process analytical technology （PAT） for pharmaceutical and some other industries. However, unlike mid-IR, NIR is known to have difficulties in monitoring crystallization or precipitation processes because the existence of solids could cause distortion of the spectra. This phenomenon, seen as unfavorable previously, is however an indication that NIR spectra contain rich information about both solids and liquids, giving the possibility of using the same instrument for multiple property characterization. In this study, transflectance NIR calibration data was obtained using solutions and slurries of varied solution concentration, particle size, solid concentration and temperature. The data was used to build calibration models for prediction of the multiple properties of both phases. Predictive models were developed for this challenging application using an approach that combines genetic algorithm （GA） and support vector machine （SVM）. GA is used for wavelength selection and SVM for mode building. The new GA-SVM approach is shown to outperform other methods including GA-PLS （partial least squares） and traditional SVM. NIR is thus successfully applied to monitoring seeded and unseeded cooling crystallization processes of L-glutamic acid.