Linear and Quadratic Relationships between Retention and Organic Modifier Content in Eluent in Reversed Phase High-Performance Liquid Chromatography: A Systematic Comparative Statistical Study

摘要

Statistical evaluation of linear and quadratic models of chromatographic retention was performed. The relationships describing reention were derived for a set of 23 carefully selected test analytes chromatographed on 18 HPLC columns using metanol-water or acetonitrile-water solutions as mobile phase. It was ascertained whether the square term in the quadratic model improves the description of chromatographic retention in a statistically significant manner. It was also checked whether the reetntion data extrapolated to a hypothetical neat water eluent (log k_w) obtained with two models and the two organic modifiers are equivalent or should be considered different. The research proved that both models vield similar results and the extrapolated log k_w values do not differs tatistically signficantly in teh case of methanol-containing mobile phases. In the case of acetonitrile-water systems the long k_w values obtained with linear and quadratic models are normally statistically different. Coorelation analysis for log k_w vs. log P parameters was performed for data determined on six columns. The best correlations were achieved employing log k_w data derived with the linear model for methanol/water systems.