Rapid Determination of Moisture in Qiju Dihuang Pills by Near-infrared Spectroscopy Technique

OBJECTIVE To establish a rapid analytical method for moisture in Qiju Dihuang Pills (condensed) by near-infrared diffuse reflectance technique. METHODS First, toluene method was used to determine the content of water in samples. At the same time, NIR diffuse reflectance spectra of 96 samples were collected. Then, Partial Least-Squares (PLS) method was used to create a quantitative model of calibration. RESULTS The correlation coefficients of the PLS calibration models of NIR spectroscopy for moisture was 0.988 09, the root-mean-square error of cross-validation (RMSECV) was 0.058 7; the correlation between the reference value of the testing sample set and the near infrared predictive value were 0.996 9; the root-mean-square error of prediction (RMSEP) was 0.075 2. CONCLUSION The method is rapid, nondestructive and accurate, which can be applied to the fast determination of moisture in Qiju Dihuang Pills (condensed).