Quantitative Fourier Transform Infrared spectroscopic investigation of humic substance functional group composition

Infrared (IR) spectroscopy has been widely used for the structural investig ation of humic substances. Although Fourier Transform Infrared (FTIR) instr umentation has been available for sometime, relatively little work with the se instruments has been reported for humic substances. IR spectroscopy, lik e other optical spectroscopies, is a quantitative technique that follows th e Beer-Lambert Law. An internal standard FTIR technique is described that a llows the quantitative comparison of specific IR absorption bands among dif ferent humic substances. The technique provides compositional information o n the functional groups present in humic substances. The FTIR technique pro duces information similar to C-13 nuclear magnetic resonance (NMR) spectros copy. However, the FTIR method requires less sample quantity and spectral a cquisition times are significantly smaller than required for C-13 NMR. This new technique extends the previous qualitative IR spectroscopic studies of humic substances to a quantitative method for the investigation of humic s ubstance structure and composition. (C) 1999 Elsevier Science Ltd. All righ ts reserved.