Detection analysis of particle size effects in overtone and combination region of NIR based on multi-types of Chinese material medica

Abstract

Near-infrared (NIR) diffuse reflectance spectroscopy was used to analyze the impact of multi-class particle size of Chinese material medica (CMM) based on the spectral characteristics in overtone and combination region. Several types of CMM (60, 80, 100,120 mesh) were subjected to NIR spectra analysis. Spectral reproducibility was examined after sample repackage. The result showed that the effects of particle size on the NIR spectra were different according to different bands, in the combination region and first combination-overtone region. Spectroscopy intensity was proportional to the particle size and influence of particle size was greater as the wavelength increased. While in the second combination-overtone region, it was inversely proportional to particle size. To the sampling loading error, the result indicated that when the mesh number was larger than 60 mesh, the error was small. The appropriate particle size was clarified to guarantee the accuracy and reliability of NIR diffuse reflectance spectroscopy in CMM.