H-POINT STANDARD ADDITIONS METHOD FOR ANALYTE DETERMINATION IN TERNARY MIXTURES

The use of the II-point standard additions method for resolving ternar y mixtures is proposed, The method calculates the analyte concentratio n from spectral data at two wavelengths where the two species selected as interferents present the same absorbance relationship. These wavel ength pairs are easily found, and can be selected to give the most pre cise results. If a matrix effect is present, use of the standard addit ions method is necessary in order to obtain good results, If there is no matrix effect, only sample absorbances and molar absorption coeffic ients are necessary, Ternary mixtures of phenol, o-cresol, 4-chlorophe nol and 3,4-dichlorophenol, which are species with highly overlapped s pectra throughout the wavelength range, were selected to test the meth od, The results obtained-are comparable to those obtained using multil inear regression.