Prediction of Boron Content in Wood Pellet Products by Near-Infrared Spectroscopy

Abstract

Abstract A rapid method assessed the potential of near-infrared spectroscopy (NIRS) to estimate boron content of wood pellet products. Based on a comparison of NIR spectra data in the 1,100- to 2,200-nm wavelength region of Eastern black spruce (Picea mariana var. mariana) wood pellets treated with preservative concentrations ranging from 0 to 2 percent and from 0 to 20 percent glycol borate–based disodium octaborate tetrahydrate (DOT), the minimum level of boric acid equivalent required to protect wood from biodegradation was revealed. Borate was indicated in the 1,700- to 1,900-nm wavelength region and the visible-NIR absorbance trended to a proportion higher for the lower borate concentrations and lower for the higher borate concentrations. These were correlated by projection to the latent structures–partial least-squares regression method and the sample-specific standard error of prediction method. Calibration sets achieved R2 values from 0.7 to 0.95, root mean square error (RMSE) ranging from 0.3 to 1.61 percent, and relative percent difference (RPD) ranging from 1.8 to 4.4, whereas validation statistics achieved R2 values from 0.64 to 0.94, RMSE ranging from 0.33 to 1.65 percent, and RPD ranging from 1.7 to 4.3. These preliminary results indicate that NIRS should be able to provide a greater quantitative and qualitative technique of predicting boron content in wood products for the preservation industry.