Application of the H-point standard additions method by using absorbance increment values as analytical signals

This paper demonstrates how the absorbance increment (DeltaA) between two wavelengths selected according to the fundamental criteria for application of the H-Point standard additions method (HPSAM) are only related to the analyte concentration. A procedure for calculation of the unknown analyte concentration with no bias error by applying HPSAM to DeltaA values in much the same way as the method of standard additions (MOSA), is reported. The method was also applied to a calibration with a single standard. The results obtained on 6 samples with maximal separations between 65 and 0 nm are reported. Finally, the proposed method was applied to the resolution of different phenol-o-cresol mixtures.