Calibrações por meio da técnica da espectroscopia no infravermelho próximo para teor de extrativos totais, de lignina total e holocelulose usando espectros obtidos na madeira sólida

Abstract

The purpose of this study was to obtain calibration curves using Near Infrared Spectroscopy Technique (NIRS) for the determination of total extractive content, total lignin, and holocellulose, using the radial face, tangential, and transversal spectra of solid wood. We used a natural hybrid of Eucalyptus urophylla owned by V & M Florestal, located in Paraopeba city (MG). The hybrid was seven years old and was planted in 3m x 3m space. The soils-proof was taken throughout the shaft. The used equipment was a Bruker spectrometer brand model MPA-R. The spectra were acquired in the range from 800 to 1,500 nm in diffuse reflection mode. The models were fitted by PLS-1 method. We used the cross-validation method, the first and second derivative pre-treatment, and removal of scattered light. For the results it is ended that: Generally, the largest correlation values were obtained starting from the average of the tangential faces, transversal and radial; the best calibrations were obtained when the pre-treatment of derivative second was applied; better results: total extractive r = 0,66 and RPD = 1,3; content of total lignin r = 0,70 and RPD = 1,5 and holocelulose content r = 0,66 and RPD = 14.