Selectivity of the binary stationary phase of cucurbituril with ionic liquid in gas chromatography
This work presents a facile strategy by integrating cucurbituril (CB7) with a guanidinium-based ionic liquid (GBIL) into a binary stationary phase for gas chromatographic separations. A CB7-IL capillary column was statically fabricated with high column efficiency of 4360 plates per m. McReynolds constants and Abraham solvation system constants were utilized to characterize the polarity and solvation properties of this new binary phase. Its selectivity and resolving ability were investigated by separation of analytes of different types, showing advantages over the neat CB7 and GBIL columns possible due to their synergistic effect. Moreover, the CB7-IL column showed good repeatability and thermal stability. The RSD values of the analytes are in the range of 0.01–0.10% for intra-day, 0.06–0.23% for inter-day and 1.5–4.7% for between-column, respectively. The proposed strategy takes full advantages of CB7 and GBIL in selectivity and separation performance and shows potential in separation science.