INFLUENCE OF ORGANIC-SOLVENT MODIFIER AND SOLVENT STRENGTH ON PEAK SHAPE OF SOME BASIC COMPOUNDS IN HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY USING A REVERSED-PHASE COLUMN

Comparative column efficiency and peak asymmetry measurements were made for 16 pyridine derivatives using approximately isoeluotropic mixtures of methanol, acetonitrile and tetrahydrofuran (THF) in combination with phosphate buffer at pH 7.0 on a RP-HPLC column suitable for the analysis of basic compounds. On average, THF and methanol gave significantly better peak shape than acetonitrile, although considerable variations in behaviour for the different derivatives were noted. Methanolic mobile phases yielded straight line plots of log k' vs. percentage of modifier; nevertheless the increase in k' with decreasing methanol concentration is accompanied by a deterioration in peak shape which varies in extent depending on the nature of the probe compound.