Preparation and Characterization of Inorganic Silica-Organic Polymer Mixture Based C16 Capillary Monolithic Column

Abstract

Abstract A novel inorganic silica-organic polymer mixed-based capillary electrochromatography monolithic column was prepared by using precursor 3-(trimethoxysilyl) propyl methacrylate with double-functional group hydrolysis/polycondensation in acidic aqueous solution, followed by double-bond co-polymerization with organic monomer hexadecyl mathacrylate under the thermal initiated condition, and the combination of preparation of silica-based monolithic column and organic polymer monolithic column was suggested. A simple operation of controlling sol mixture using mercury infusion when the mixture infused into capillary was raised to acquire smooth interface of stationary phase. The preparation conditions of monolithic column were optimized. The structure of the monolithic columns was characterized by SEM images and nitrogen absorption method, and the results showed that the median pore diameter of the materials was in the range of 3 to 7 nm with average surface area of 103.4 M2 g−1. The influence of buffer concentration, pH value, and organic modifier content on electroosmotic flow (EOF) velocity has been investigated. Seven neutral aromatic hydrocarbons were baseline separated with column efficiency of naphthalene up to 54000 plates m−1. The reproducibility for separation time and retention factor was given in terms of RSD values at 0.9% and 0.6% (n = 5) for run-to-run injections and 1.2% and 0.8% (n = 3) for day-to-day operations. The RSD values of separation time and capacity factor of different columns (n = 3) were 8.7 and 5.7%, respectively. The studies on performance of columns indicated that the columns possess typical reverse retention mechanism.