Poly(3-hexylthiophene) stationary phase for gas chromatographic separations of aliphatic and aromatic isomers.

This work describes the investigation of utilizing a chain-typed thiophene-based π-conjugated polymer, i.e., poly(3-hexylthiophene) (P3HT), as the stationary phase for gas chromatography (GC). The P3HT column was statically prepared and investigated for its column efficiency, polarity, separation performance, repeatability and thermal stability. As a result, it showed moderate polarity and column efficiencies of 3260, 3310 and 3790 plates/m for 1-octanol, naphthalene and n-dodecane, respectively. As evidenced, it exhibited high-resolution performance for aliphatic and aromatic isomers, including those critical pairs such as phenanthrene/anthracene and p-/m-benzenediol isomers. Moreover, it displayed stronger retention for alkanes, alcohols and phenols in comparison to the polysiloxane stationary phase with close polarity. Also, the P3HT column had good repeatability and reproducibility with the RSD values less than 0.05% for run-to-run, 0.17-0.54% for day-to-day and 2.7-5.2% for column-to-column, and good thermal stability up to 260 °C. This work demonstrates the promising future of the thiophene-based polymer and its derivatives in separation science.

Performance and selectivity of dicyanuric-functionalized polycaprolactone as stationary phase for capillary gas chromatography.

Dicyanuric-functionalized polycaprolactone (DPCL) was explored for its separation performance in gas chromatography (GC). The statically coated DPCL capillary column (0.25mm, i.d.) showed column efficiency of 3460 plates/m determined by naphthalene at 120°C. McReynolds constants and Abrahams system constants were also determined to evaluate the polarity and possible molecular interactions of the stationary phase. As a result, DPCL column exhibited excellent separation performance for diverse types of analytes with good peak shapes. Most interestingly, it shows unique amphiphilic selectivity and high-resolution capability for both apolar to polar isomers. In addition, DPCL column had good column repeatability with the RSD values below 0.06% for run-to-run, 0.09-0.40% for day-to-day and 1.7-3.6% for column-to-column, and good thermal stability up to 280°C. The high selectivity and resolving capability demonstrate the great advantages of the DPCL stationary phase for simultaneous determination of analytes of great variety in complex samples.

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.