[Fast measurement method based on near infrared spectroscopy in extraction process of Tianshu capsules]

Based on the near infrared spectroscopy, partial least square (PLS) method was used to respectively develop the quantitative calibration models to fast measure the contents of the total solid and ferulic acid in extraction process of Tianshu capsule extracts. The results showed that in the quantitative model of solid content, the correlation coefficients (R²) of calibration set and cross validation set were 0.967 301 and 0.947 726. The root-mean square error of calibration set (RMSEC) was 0.054 7 and root-mean square error of cross validation set (RMSECV) was 0.069 8. Besides, in the quantitative model of ferulic acid, the correlation coefficients (R²) of calibration set and cross validation set were 0.986 879 and 0.962 243. RMSEC was 1.402 6 and RMSECV was 2.400 2. When the established models were applied to on-line monitoring, the correlation coefficients of predicted results and measured values for total solid content and ferulic acid were 0.993 3 and 0.991 6; root-mean square error of predicted value (RMSEP) was 0.039 3 and 1.669 3 respectively; mean relative deviation of predicted value (RSEP) was 3.49% and 3.58%. The results indicated that the established models can be used to fast measure the contents of the total solid and ferulic acid in extraction process of Tianshu capsule extracts.