In order to prepare zwitterionic HILIC monolithic columns with high polarity, the highly hydrophilic monomer N , N -dimethyl- N -acryloyloxyethyl- N -(3-sulfopropyl)ammonium betaine (SPDA) and crosslinker N , N ′-methylenebisacrylamide (MBA) were employed for developing a novel sulfoalkylbetaine type stationary phase. The polymerization parameters were systematically optimized in order to obtain a satisfactory performance for column permeability, mechanical stability, hydrophilicity, efficiency and selectivity. Compared to the previously reported poly( N , N -dimethyl- N -methacryloxyethyl- N -(3-sulfopropyl)ammonium betaine- co -ethylene dimethacrylate) (poly(SPE- co -EDMA)) monolith and the poly(SPDA- co -EDMA) monolith that we developed, a significantly enhanced hydrophilicity was obtained on the poly(SPDA- co -MBA) monolithic column, illustrated by the lowered critical composition of the mobile phase corresponding to the transition from the HILIC to the RP mode. Excellent permeability, reproducibility and stability were achieved on this optimized poly(SPDA- co -MBA) monolith. A column efficiency of 70,000 plates/m was obtained for the analysis of bases at a linear velocity of 1.95 mm/s. As expected, by studying the influence of mobile phase pH and salt concentration on their retention, a weak electrostatic repulsion interaction for negatively charged analytes was also observed at low organic solvent content on the poly(SPDA- co -MBA) monolithic column. The final optimized poly(SPDA- co -MBA) monolith exhibited good selectivity for a series of polar compounds, such as phenols, bases, benzoic acid derivatives, small peptides, urea and allantoin.
There are great challenges in the field of natural product isolation and purification and in the pharmacological study of oligosaccharide monomers. And these isolation and purification processes are still universal problems in the study of natural products (NPs), traditional Chinese medicine (TCM), omics, etc. The same polymer-modified materials designed for the special separation of oligosaccharides, named Sil-epoxy-PEI and Sil-chloropropyl-PEI, were synthesized via two different methods and characterized by scanning electron microscopy combined with energy spectrum analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, zeta potential as well as surface area analysis, etc. Several nucleotide/nucleoside molecules with different polarities and selectivities were successfully isolated in our laboratory using stainless-steel columns filled with the synthesized material. In addition, the separation of saccharide probes and oligosaccharides mixtures in water extracts of Morinda officinalis were compared in HILIC mode. The results showed that the resolution of separations for the representative analytes of the Sil-epoxy-PEI column was higher than for the Sil-chloropropyl-PEI column, and the developed stationary phase exhibited improved performance compared to hydrothermal carbon, amide columns and other HILIC materials previously reported.
危险品化学品经营许可证（带存储）