Progress in pKa Determination Technology: Case Studies in Low and High Soluble Flavonoids

Purpose. This study aimed to investigate the accuracy of software to predict the ionization constants, pKa for a variety of flavonoids.

Conclusion. Flavonoids exhibit several challenges to accurate pKa measurement, including low solubility and potential oxidative degradation. Cosolvents ensured that the compounds were completely in solution during the titration. While the assignments made herein are tentative, they suggest that the beta hydroxy group may undergo internal hydrogen bonding that may be incorporated into some commercially available software programs, thus providing better agreement between measured and predicted values. Future work will focus on investigating some of the underlying chemistry further.