ABSTRACT
A multiwavelength spectrophotometric method, called Dip-Probe Absorption Spectroscopy (D-PAS), developed previously for pKa determination was applied for the determination of the molar absorption coefficients of ionizable compounds. Specifically, the spectral data obtained from a spectrophotometric titration are resolved using Target Factor Analysis (TFA) to generate the molar absorption coefficients of each ionizing species. The D-PAS method has been exemplified by the spectral data of p-aminosalicylic acid and nicotinic acid. It has been shown that the molar absorption coefficients as determined by the D-PAS method are comparable to those deduced by manual titration experiment.