From several ultraviolet (UV) absorption curves of mixed solutions containing more than two components, two molecular extinction coefficients at a certain wave length were calculated by the least-squares method. When this procedure was repeated at appropriate intervals over all UV range, an absorption curve of the desired component was obtained. The accuracy of this method was checked by using some mixed solutions of cinnamic acid and benzoic acid, benzylideneacetone and benzoylacetone, Furthermore, the procedure was applied to the quaternization reaction of methyl p-nitrobenzoate with trimethylamine in methanolic solution.
