Retention properties of a cyanopropylsiloxane‐bonded silica‐based sorbent for solid‐phase extraction

Abstract

Abstract The characteristic kinetic and retention properties of a silica‐based cyanopropylsiloxane‐bonded sorbent for solid‐phase extraction are described. Abraham′s solvation parameter model is used to characterize the contribution of individual intermolecular interactions to retention under liquid chromatographic and sample processing conditions with aqueous methanol mixtures as the mobile phase. The main features governing retention by the sorbent are the solute's size and hydrogen‐bond basicity; interactions of a dipole type are not significant when aqueous methanol solutions are employed as the mobile phase. Compared to typical silica‐based octadecylsioxane‐bonded sorbents the greater difficulty of forming a cavity in the solvated cyanopropylsiloxane‐bonded sorbent more than offsets the more favorable dipole‐type and solute hydrogenbond base interactions of the cyanopropylsiloxane‐bonded sorbent. It is shown that there are no practical circumstances for which a cyanopropylsiloxane‐bonded sorbent would be more useful than a typical ODS sorbent for the isolation of organic non‐electrolytes from water by solid‐phase extraction.