pK(a) determinations by using a HPLC equipped with DAD as a flow injection apparatus

被引:16
作者
Ando, HY
Heimbach, T
机构
[1] Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Company, Ann Arbor, MI 48 105
关键词
apparent pK(a); automation; constant ionic strength; DAD; diode array detector; experimental pK(a); FIA; flow injection analysis; HPLC; ionization constants; non-aqueous solvents; spectroscopic pK(a) determination; universal buffer; UV-Vis;
D O I
10.1016/S0731-7085(97)00084-8
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
A semi-automated method to determine pK(a) 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 pK(a) values obtained for two model compounds, benzoic acid (similar to 4.0) and 2-aminopyridine (similar to 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 pK, values, often seen when using non-aqueous solvents, was small (0.04-0.40 pH units) compared to conventional methods. (C) 1997 Elsevier Science B.V.
引用
收藏
页码:31 / 37
页数:7
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