In-situ growth of a metal organic framework composed of zinc(II), adeninate and biphenyldicarboxylate as a stationary phase for open-tubular capillary electrochromatography

This work reports on the in-situ growth of a metal organic framework (MOF) composed of zinc(II), adeninate and biphenyldicarboxylate on the inner wall of a capillary, and the use of this MOF as a stationary phases in open-tubular capillary electrochromatography. The inner wall of a fused-silica capillary was first modified with 3-aminopropyltriethoxysilane to create surface amino sites, and then the MOF was synthesized by in-situ growth. The modified capillary was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The results proved the successful growth of the MOF. The resultant open-tubular column showed good separation selectivity towards neutral compounds, acidic and basic compounds including nonsteroidal anti-inflammatory drugs, sulfa drugs and small biomolecules. In addition, the modified column is stable and repeatable. The precisions (expressed as RSDs) of the retention time for intra-day (n = 5) and inter-day (n = 5) separations and between columns (n = 3) are less than 0.5, 1.6 and 4.7%, respectively. Conceivably, this new kind of MOF represents a most useful novel stationary phase in electrochromatographic separations.