Preparation And Performance Research Of A Novel Reversed-Phase Hybrid Monolithic Capillary Column

Capillary electrochromatography (CEC) demonstrates huge potential in satisfying these requirements as it combines many merits of both high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). as the "heart" of CEC, the CEC column plays an important role in separation performance of the CEC. The monolith columns, as the most promising CEC columns, have been attracting more and more attentions, due to its easy preparation, good permeability and fast mass transfer etc compared with the traditional particle packed columns. Hence, the preparation of monolithic column has become new attracting technologies in past few decades.In our work, a novel C18reversed-phase hybrid monolithic capillary column using VC18HIm+Br-as organic monomer was prepared via "one-pot" approach Through a large number of experiments, VC18HIm+Br-groups were successfully anchored into the monolithic matrix by the polycondensation of TEOS and VTES as well as in situ copolymerization of VC18HIm+Br-and vinyl group on the VTES with CTAB as supramolecular template, AIBN as initiator, ammonia water as catalyst. The effects of experimental variables during the hybrid monoliths formation, such as TEOS/VTES volume ratio, content of H2O, polycondensation temperature, amount of supermolecule template (CTAB) and organic monomer, i-PrOH/n-BuOH volume ratio, concentration of ammonia water were investigated in detail. At last, the prepared column was characterized with different manners and the separation performance was also researched.Under the optimal conditions, the prepared VC18HIm+Br-hybrid monolithic column exhibited homogenous and porous skeleton structure with excellent permeability and good mechanical stability, and the Fourier transform infrared (FT-IR) clearly proved the successful modification of VC18HIm+Br-onto the monoliths. What’s more, the monolithic column was applied to separate various neutral, basic analytes, some amino acids as well as protein samples in capillary electrochromatography. According to these results, it could be seen that the separation of neutral analytes on the VC18HIm+Br-monolith was mainly depended on typical reverse phase (RP) chromatographic retention mechanism and the separation mechanism of charged compounds could be the combination of SAX and hydrophobic interaction as well as the effect of electrophoresis. Besides, the conventional peak tailing problem was not appeared when separating the basic compounds. All results showed the columns possessed highly efficient and stable separation ability which indicated the monolithic column would be widely applied in separation filed.