1. A multicomponent quantitative analytical method for use with an analytical instrument comprising the steps of: obtaining calibration values related to spectra for a select number of calibration samples containing predetermined concentrations of selected analytes such that information regarding spectra values proportional to the concentrations of the selected analytes is determined; performing a transformation of the spectra calibration values using a transform to obtain orthogonal basis vectors; performing a multivariate analysis to obtain a calibration value matrix relating known concentrations of analytes in the calibration sample to the transformed spectra calibration values; obtaining values of an unknown spectrum for a sample containing unknown concentrations of analytes; performing a transformation of the values of the unknown spectrum using said transform having the property of orthogonality; determining the concentrations of the analytes in the sample using the transformed values of the unknown spectrum and the calibration value matrix; and displaying or storing information of the concentrations of the analytes.