Rapid quantification of epigoitrin in the extraction process of Radix Isatidis using near infrared spectroscopy

Abstract

Near-infrared Spectroscopy (NIR) is widely accepted as an efficient technology for process control in the production of traditional Chinese medicine (TCM). This study was to establish a NIR-based approach to determining epigoitrin of Radix Isatidis during temperature-controlled extraction process. 86 extracts of Radix Isatidis were prepared in 50 °C water for 4 hours, and were randomly divided into validation set and calibration set. The concentration of epigoitrin of each sample was determined by HPLC/UV, and correspondingly NIR spectra of those samples were also acquired. Partial least square (PLS) algorithm was utilized to develop a predictive model on NIR spectra data and contents of epigoitrin in samples of calibration set. The model displays good performance with acceptable values of SECV, SEC, LV and R2, and it was applied to predict the concentration of epigoitrin in samples of validation set from their NIR data. As a result, the model produced accurate result with little deviation between predicted values and experimental values. The proposed NIR method is expected to be developed as a promising approach for process control in TCM production.