Prediction of the pH in wood by diffuse reflectance infrared Fourier transform spectroscopy

The diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) sp ectrum of the peeled wood of kenaf (Hibiscus cannabinus L.), cotton (Gossyp ium barbadense), and pine (Pinus brutia) revealed three broad absorptions i n the region of 1800-1540 cm(-1), The deconvolution of spectra in this regi on revealed the existence of 10 major peaks contributing to that spectrum i n the aforementioned region. The absorption peaks at 1710 and 1608 cm(-1) h ave been assigned to carboxylic (-COOH) and carboxylate (-COO-) groups, res pectively, Since their relative size is pH dependent, the ratio of their ar ea was used as a pH indicator, A linear relationship was then established b etween that ratio and the amount of acid need to bring the pH of the wood t o 3, as it is measured by the pH determination of a water extract of the wo od. This is the pH at which the wood is processed during manufacturing of c hipboards.