Terahertz spectroscopy applied to quantitative determination of harmful additives in medicinal herbs

Abstract In this study, terahertz (THz) spectroscopy was used in combination with an improved partial least squares (PLS) method to quantitatively determine the harmful additives Auramine O in medicinal herb Pollen Typhae. A terahertz time-domain spectroscopy (THz-TDS) transmission system was built to collect the absorbance spectra, and stacked partial least squares based on variable contribution sorting (VIP-SPLS) was used to establish the correlation between the absorbance and the content of Auramine O. Compared with original PLS and SPLS, VIP-SPLS obtained a better performance. The results in this study indicated that THz spectroscopy combined with VIP-PLSR has a potential for the rapid and non-destructive prediction of harmful additives residue.