Adaptation of characteristic vector analysis and titration curve analysis for calculations of pKBH+ from ultraviolet–visible spectral data

Abstract

Equilibrium constants for protonation, K_BH⁺, have been extensively investigated by u.v.–visible spectrophotometry in sulphuric acid. To overcome difficulties in calculating the pK_BH⁺ values, experimental data were used for estimating two main orthogonal characteristic vectors contributing to the total variability in absorption. The largest amount of variability was associated with the spectral change accompanying protonation and the reconstituted absorption curves were calculated. A new, one-step computer procedure is proposed for calculation of pK_BH⁺ by the use of characteristic vector analysis and titration curve analysis.