SELECTIVITY STUDIES ON BRANCHED AND LINEAR ALKYL BONDED STATIONARY PHASES IN REVERSED-PHASE LIQUID-CHROMATOGRAPHY

Reversed-phase liquid chromatographic retention characteristics for the sixteen acyclic C1-C5 N-alkylbenzamide congeners were measured on various branched and linear, alkyl bonded hydrocarbon stationary phases. Retention factors, k1, were determined in acetonitrile-water mobile phase compositions on ethyl, n-octyl, n-dodecyl, n-octadecyl, 1-ethyladamantyl, 4-butyloctyl, and 2,4,4-trimethylpentyl stationary phases. Statistical analysis of the two main effects investigated - type of stationary phase and percentage of organic modifier (acetonitrile) in the mobile phase - described greater than ninety percent of the variability in the data for most of the comparisons. Selectivity effects due to variation in the mobile phase dominated the results.