Preparation and characteristics of two novel calix[4]arene polysiloxane stationary phases for capillary gas chromatography

Abstract

Two novel calix[4]arene derivatives, 5-1′,1′-dimethylundecyloxyphenylmethyl-11,17,23-tris-1″, 1″-dimethylethyl- 25,26,27,28-tetrabenzyloxycalix[4]arene polysiloxane (C[4]TB-PSO) and 5-1′,1′-dimethylundecyloxyphenyl- methyl-11,17,23-tris-1″,1″-dimethylethyl- 25,26,27,28-tetraethoxycarbonylmethyloxycalix[4]arene polysiloxane (C[4]TECM-PSO), were synthesized and used as stationary phases in capillary gas chromatography. The new phases demonstrated high column efficiency, a wide operating temperature range, high thermal stability, medium polarity and excellent selectivity towards alcohol isomers and positional isomers of aromatic compounds. The selectivity mechanism for positional isomer compounds was investigated by the measurements of thermodynamic parameters, ΔH, ΔS and ΔG. The inclusion properties of the calix[4]arenes are discussed.