[Determination of holocellulose and lignin content in Chinese fir by near infrared spectroscopy].

The contents of holocellulose and lignin of wood are important determinants of the pulping quality of wood. The determination of holocellulose and lignin contents using traditional chemical methods is a costly and time-consuming process. Near infrared reflectance (NIR) analysis offers a fast, nondestructive testing and low cost alternative for prediction of wood quality. In the present article, the total amounts of holocellulose and lignin contents of 48 samples were analyzed according to standard wet-chemical method. All samples were milled using a Standard Wiley knife mill with a 2 mm screen. The 2 mm material was sieved with a 40-60 mesh sieve. Then, near infrared (NIR) spectra were collected in diffuse reflectance from samples of meal contained in a spinning cup by an analytical spectral devices (ASD) Lab Spec at wavelengths between 350 nm and 2 500 nm. The raw spectra were pretreated by the second derivative and smoothing, then the NIR model was built using partial least-squares statistical analysis and full cross validation. The coefficients of correlation (r) of calibration and validation for holocellulose were 0. 96 and 0.93, respectively; the standard error of calibration (SEC) and the standard error of prediction (SEP) were 0.39 and 0.50, respectively. For lignin, the values for r of calibration and validation were 0.99 and 0.90, while the SEC and SEP were 0.10 and 0.28, respectively. It was concluded that NIR analysis is a reliable, fast and nondestructive testing predictor of holocellulose and lignin content of wood in Chinese fir.