Preparation of mixed stationary phase of cellulose and polysiloxane ionic liquid for gas chromatography

Abstract

Cellulose has been widely used to synthesize chiral stationary phases for liquid chro- matography, but it is still absent in the family of stationary phases of gas chromatography due to its poor film-forming property. Based on the unique dissolution characteristic, ionic liquids provide a great chance to solve this problem. In this paper, cellulose triacetate (CTA) was syn- thesized, and then mixed with the home-made polysiloxane ionic liquid (PIL-C12-NTf2) to pro- duce a novel mixed stationary phase (CTA@ PIL-C12-NTf2). After that, it was used to prepare a capillary column for gas chromatography. The column efficiency was measured to be 3,165 plates/m (110 °C, naphthalene, k = 4.95), demonstrating the excellent film-forming capability of this stationary phase, and then the solvation parameter model was employed to find out the interaction parameters of CTA@ PIL-C12-NTf2. In the aspect of selectivity, CTA was firstly demonstrated to be able to improve the resolutions of tri-substituted aromatic positional isomers and the six isomers of nonane (C9). Moreover, some mixtures of representative chemicals like di-substituted aromatic positional isomers, n-alkanes, alcohols, aliphatic esters and phthalates can also be separated well on CTA@ PIL-C12-NTf2. This work proposed a novel way for the application of cellulose modified stationary phase of gas chromatography, and revealed some features of this stationary phase in selectivity resulting from cellulose.