Measurement of moisture content in 5 kinds of TCM extracts with near infrared diffuse reflectance spectroscopy

Objective:Near infrared diffuse reflectance spectroscopy was used for measurement of moisture content in 5 kinds of traditional Chinese medicine extracts,namely Radix Scutellariae,Forsythia suspense,Flos Lonicerae,Cornu gorais,and Bear gall powder.And the general rule of determining the moisture content with NIR was summarized according to the experimental results.Method:The spectra were recorded with the average of 64 scans over the spectral region 4000-10000 cm-1 at 8 cm-1 intervals.The wavebands containing 3 characteristic wavelengths of water(6900,5200,5180 cm-1)were selected,and were pretreated with Multiplicative Scatter Correction,Savitzky-Golay filt,and first derivative.The calibration between the NIR spectra and the reference values of moisture content was obtained with Partial Linear Squares method and optimized through inner cross validation and external validation.Result:The coefficients of correlation of inner cross validation and external validation are both above 0.90,and the RMSECV and RMSEP are both below 0.05.The calibration models were used for testing a new set of samples,and the results were satisfied.Conclusion:The presented method is timesaving and accuracy,which indicates potential to be widely used in the moisture content determination of TCM extracts.