High-resolution separation performance of poly(caprolactone)diol for challenging isomers of xylenes, phenols and anilines by capillary gas chromatography.

Efficient separation of xylenes, phenols and anilines is a big issue in chemical and petroleum industries. This work presents the first example of employing poly (caprolactone) diol (PCL-Diol) as stationary phase for high-resolution gas chromatographic (GC) separations of these tough isomer mixtures. It showed medium polarity and stronger H-bonding basicity than H-bonding acidity. Impressively, PCL-Diol column exhibited extremely high resolving capability for the isomer mixtures of xylenes, cresols/xylenols, and toluidines/xylidines with good peak shapes. Moreover, it exhibited preferential retention for analytes of a linear alkyl chain, suggesting its shape fitting selectivity for specific analytes. In addition, its separation performance has good repeatability with RSD values on retention times below 0.01% for run to run (n=6), 0.67-0.80% for day to day (n=4) and 3.2-4.4% for column to column (n=4) repeatability, respectively. Furthermore, it was applied for the determination of isomer impurities in real samples, showing good potential for practical use. This work demonstrates the advantageous high-resolution separation performance for challenging isomers and shows its promising future of PCL-Diol-based materials in separation science.