pKa determinations by using a HPLC equipped with DAD as a flow injection apparatus

Journal of Pharmaceutical and Biomedical Analysis
H Y Ando, T Heimbach

Abstract

A semi-automated method to determine pKa values spectrophotometrically is described. The method uses the capabilities of a HPLC equipped with a diode array detector (DAD) as a flow injection apparatus. The advantages are low sample consumption, rapid sample throughput, high sensitivity, and precision. Experimental pKa values obtained for two model compounds, benzoic acid (approximately 4.0) and 2-aminopyridine (approximately 6.8), are consistent with literature values. Constant ionic strength was maintained for a wide pH range. Solubilized samples in non-aqueous solvents were also investigated. The weakening in pKa values, often seen when using non-aqueous solvents, was small (0.04-0.40 pH units) compared to conventional methods.

Citations

Sep 15, 2014·Journal of Chromatography. a·Bradley J VanMiddlesworth, Apryll M Stalcup
Mar 23, 2012·Pharmaceutical Development and Technology·Noble KuntworbeRaida Al-Kassas
Feb 9, 2000·Biomedical Chromatography : BMC·S Agatonović-KustrinI G Tucker
Dec 5, 2016·Journal of Pharmaceutical and Biomedical Analysis·Tereza VolnáJan Hlaváč

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