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In this work, an innovative ionic liquid functionalized star-shaped polymer is synthesized by coupling star-polycaprolactone with benzimidazolium (star-PCL-Bim), and statically coated into a capillary column for gas chromatographic (GC) separations. The fabricated star-PCL-Bim capillary column with moderate-polar nature reveals a high column efficiency of 3598 plates/m for n-dodecane at 120 °C, and advantageous distinguishing ability (R > 1.5) for 9 aromatic isomer mixtures and 12 cis-/trans-isomers. Its excellent resolving capacity can be credited to the architecture of star-PCL-Bim, the PCL arms, and π-electron-rich benzimidazolium cations, and it results in a quite different retention behavior of star-PCL-Bim from that of star-PCL and commercial HP-35 columns, with "dual-nature" selectivity in separating a mixture including 29 compounds. These favorable chromatographic characteristics demonstrate the great application potential of this material in GC, and provide a prospective strategy to obtain high-performance stationary phases. [ABSTRACT FROM AUTHOR]

The separation of aromatic isomers, in particular xylene isomers, represents a big issue in chemical and petroleum industries, owing to their similar molecular sizes and boiling points. In this work, the investigation ofpillar[6]arene derivative modified by long alkyl chains (P6A-C10) as a stationary phase for high-resolution gas chromatographic (GC) separations of xylene isomers is presented. Pillar[n]arenes are a new class of macrocyclic hosts that can accommodate specific guests due to their highly symmetrical and rigid pillar architectures with π -electron rich cavities. The P6A-C10 column showed high-resolution performance towards xylene isomers, with peculiar advantages if compared with the commercial HP-5, HP-35, DB-17, and PEG-20Mcolumns.A quantum chemistry calculation has been performed, showing a difference in non-covalent interactions with the P6A-C10 pillar framework, which leads to specific selectivity for xylene isomers.Furthermore, the P6A-C10 column exhibited good repeatability. [Display omitted] • Novel pillararene-based stationary phase. • High resolving performance towards xylene and other aromatic isomers. • Advantageous performance of the P6A-C10 column over the commercial HP-5, HP-35, DB-17, and PEG-20 M columns. • Quantum chemistry calculation was utilized to assess the separation mechanism. [ABSTRACT FROM AUTHOR]

• Amphiphilic pillar[5]arene (P5A-C10-2NH 2) as GC stationary phase. • High resolving performance towards a wide range of analytes and isomers • Multiple recognition interactions with analytes • Quantum chemistry calculation was utilized to assess the separation mechanism. Pillar[ n ]arenes possess highly symmetrical and rigid pillar-shaped architecture with π -electron rich cavity that afford their reliable host-guest recognition interactions towards matched guests. In this work, a novel amphiphilic pillar[5]arene (P5A-C10-2NH 2) was designed, synthesized and employed as the stationary phase for capillary gas chromatography. To date, they have not been reported in the field of chromatography. The P5A-C10-2NH 2 capillary column (10 m × 0.25 mm i.d.) was prepared by static coating method. Its capillary column exhibited moderate polarity and column efficiency of 2265 plates/m determined by naphthalene at 120 °C. As evidenced, the P5A-C10-2NH 2 column achieved advantageous separation performance for a mixture of 24 analytes of diverse types and exhibited different chromatographic selectivity from two pillar[5]arene derivatives columns and commercial HP-35 column with 35%-phenyl-methylpolysiloxane. Moreover, the P5A-C10-2NH 2 column baseline resolved more than a dozen positional and cis - trans isomers. Furthermore, the separation mechanism of P5A-C10-2NH 2 column was discussed by quantum chemical calculations. In addition, the P5A-C10-2NH 2 column had high thermal stability and excellent separation repeatability 0.01–0.04% for run-to-run, 0.03–0.17% for day-to-day and 3.2–3.9% for column-to-column. The special amphiphilic structure and high resolution for various analytes reveal the good potential of pillararenes as a new class of stationary phases for chromatographic analyses. Moreover, the TPG column achieved improved thermal stability over the GIL column and excellent repeatability. [ABSTRACT FROM AUTHOR]