General
Two-Step
Method for the Fabrication of Covalent-Organic
Framework-Bound Open-Tubular Capillary Columns for High-Resolution
Gas Chromatography Separation of Isomers
posted on 2023-11-15, 03:03authored byWen-Chao Deng, Hai-Long Qian, Cheng Yang, Shu-Ting Xu, Xiu-Ping Yan
Covalent organic frameworks (COFs)
are promising as stationary
phases for gas chromatography (GC). The successful anchoring of COFs
to the inner walls of the capillary with good uniformity is an important
prerequisite to ensure the excellent separation performance of columns.
However, current methods for the fabrication of COF-based capillary
columns cannot always meet this requirement when faced with different
COFs, which hampers the further development of COF-based GC stationary
phases. Here, we show a general two-step method for the fabrication
of COF-bound capillary column. The first step enables the formation
of uniform amorphous polymer layer on the inner walls of capillary,
while the second step allows the facile transformation of the amorphous
polymer layer into a highly crystalline COF layer. COF-bound capillary
columns with different framework structures were fabricated successfully
by the developed two-step method. Impressively, the COF layers bound
on the inner walls of these capillary columns showed good uniformity
and high crystallinity. More importantly, as an example, the fabricated
Tab-DHTA-bound capillary column showed good resolution (R > 1.5) and high column efficiency (700–39,663 plates m–1) for the tested isomers of ethylbenzene, xylene,
dichlorobenzene, chlorotoluene, pinene, 1,3-dichloropropene, and propylbenzene
with good precision (RSD, run-to-run, n = 5) (retention
time, 0.2–0.6%; peak area, 0.5–1.1%; and peak height,
0.5–1.4%). In general, the fabricated Tab-DHTA-bound capillary
column exhibited better performance for the separation isomers than
commercial columns DB-5 and HP-FFAP. These results indicate that the
two-step method is an efficient way to fabricate the COF-bound capillary
column with excellent separation performance.