RELATIONS BETWEEN MIDINFRARED AND NEAR-INFRARED SPECTRA DETECTED BY ANALYSIS OF VARIANCE OF AN INTERVARIABLE DATA MATRIX

A mathematical procedure based on the analysis of variance of an inter variable data matrix (AVID) was used to relate wavenumbers and wavelen gths between the mid-infrared and near-infrared domains. Initially the method calculates for each sample the product of intensities at all c ombinations of the frequencies in the two domains. This data matrix is submitted to analysis of variance (ANOVA) based on a classification c riterion, This procedure gives a matrix of Fisher F values for all pos sible combinations of wavenumbers and wavelengths. To remove the maski ng effect due to a few extremely significant frequencies and to highli ght the relations between the frequencies, this matrix of F values was corrected bg subtraction of a matrix of independence. The examination of the corrected data matrix allowed the assignment of the most impor tant peaks for the discriminating criterion, This procedure also allow s the study of vector profiles, where one spectral domain is examined in relation to a particular frequency in the other domain, The study o f vector profiles is a very useful tool to see the relations between t he wavenumbers and wavelengths of the two domains under study.