Signal Enhancement and Elimination of Water-Vapor Interference in Fourier-Transformed Infrared Photoacoustic Spectroscopy of Powdered Plant Materials

Abstract

A simple and efficient method to enhance the Fourier-transformed infrared photoacoustic signal from powdered samples of plant materials is described. The increase in signal strength appears to be inversely related to the rate of absorption of added water by the dry cellulose, starch, lignin, and hemicellulose of the plant. The method also provides an accurate and convenient technique for obtaining photoacoustic infrared spectra of powdered plant materials free of interference from incidental water vapor in the sample. A hypothesis to account for the nonlinear behavior of the interference is proposed.