Retention behaviour of C1–C4 hydrocarbons on copper(II) complexes of cyano- and mercaptopropyl bonded phases

Abstract

The retention behaviour of light (C₁–C₄) hydrocarbons on micropacked cyano- and mercaptopropyl bonded silica columns and their copper(II) complexes was examined by GC under isothermal conditions (25 °C). All the phases gave excellent separation of a mixture of methane, ethane, propane and butane with high reproducibility of retention times. Presumably due to specific metal-olefin interactions, the metal-containing packings gave a better separation of a ten-component mixture of C₁–C₄ saturated and unsaturated hydrocarbons. However, this effect appears to be weaker than the dispersive interactions between the solutes and the hydrocarbon chains of the bonded ligands as their chromatograms are similar to those obtained on micropacked n-alkyl and bidentate alkylsilane silica columns. Among the phases examined, a 3 m column of cyanopropyl-copper(II) complex offered a better resolution of a ten-component mixture of C₁–C₄ hydrocarbons.