[An authentication method of bear bile powder based on the near infrared spectroscopy]

A method based on the near infrared (NIR) spectroscopy was established for the authentication of bear bile powder and the quantitative analysis of the proportion in the counterfeits. The NIR spectra of 30 bear bile powder samples from 4 different origins, 6 pig gall powder samples, and 65 mixed samples of bear bile powder and pig gall powder with different proportions range from 0 to 100% were collected. The principal component analysis (PCA) was done and well-marked boundaries were observed between the bear bile and the counterfeits, also the bear bile samples from different origins. Partial least squares discriminant analysis (PLS-DA) was used to differentiate the bear bile and the counterfeits, and the rate of accuracy is 95%. Finally, the PLS calibration model was established for the quantitative analysis of the bear bile proportion in the counterfeits, the coefficient of determination of the prediction set is 0.9759, and the root-mean-square prediction error is 4.25%, which indicated that the result was satisfied. This research contributes to the rapid and undamaged identification of bear bile powder, and also offers reference for the quality identification of other expensive medicinal materials.