The determination of the concentrations of several analytes in a sample by measuring its absorbance at many different wavelengths is reviewed, with specific emphasis on prediction uncertainty. The standard concentration error can be estimated by an equation resembling the well-known expression for the univariate case. Spectra for aqueous mixtures of potassium permanganate and potassium dichromate at a suitable pH are studied, and the concentrations are calculated including the proper uncertainty estimates.
Cabezón et al. (2006) studied this question.