Development of a new C₁₄ monolithic silica column containing embedded polar groups for pressurized capillary electrochromatography

Abstract

Monolithic columns have been prepared with a novel bonded silica stationary phase, tetradecylamine bonded silica (TDAS), and used in pressurized capillary electrochromatography (pCEC). The monolithic silica column matrix was prepared by a sol-gel process and then chemically modified with the spacer (3-glycidoxypropyl)trimethoxysilane and tetradecylamine. The introduced embedded polar amine groups dominated the charge on the surface of the monolithic stationary phase and generated an EOF from cathode to anode under acidic conditions. The tetradecyl hydrophobic chains in TDAS provide chromatographic interactions. The chromatographic characteristics of the prepared monolithic column were studied. Some aromatic compounds including alkylbenzenes, aromatic hydrocarbons, phenols, and anilines were successfully separated on the TDAS monolithic column in pCEC mode. As expected, the TDAS monolithic stationary phases exhibit typical reversed-phase electrochromatographic behavior toward neutral solutes due to the introduced tetradecyl groups. Hydrophobic as well as electrophoretic migration processes within the monoliths were observed in the separation of basic anilines. Symmetrical peaks can be obtained for anilines because the embedded polar amine groups on the surface can effectively shield the adsorption of positively charged analytes onto the stationary phase.

Polar-Embedded and Polar-Endcapped Stationary Phases for LC

“…A phase containing both ether and amino embedded groups (and a hydroxyl group) has been used in CEC (Ye, Li, and Zhao 2007). This gave improved peak symmetry for anilines as the positively charged amino-embedded group prevented adsorption of analyte onto the surface.…”

Application and optimization of organic–inorganic hybrid monolithic capillary electrochromatography for in vivo cefdinir determination with microdialysis

“…pH values greatly influence separation, based on the results from the experiments (9,19,20), the resolution was lower when this value was above or below 4.5. This was attributed to the characteristics of the monolith and the target compound.…”

“…The combination of the two offers a promising alternative. It was shown that a hybrid organic–inorganic monolithic column incorporates the organic functional moieties into the inorganic silica monolith by the sol–gel process, which yields various properties . Compared with the conventional procedure that involves forming a silica matrix and subsequent chemical bonding, direct incorporation of organosiloxanes was more preferable attributed to its better hydrolytic stability at low pH values.…”

Preparation and characterization of silica monolith modified with bovine serum albumin‐gold nanoparticles conjugates and its use as chiral stationary phases for capillary electrochromatography

“…The GNPs were synthesized based on the sodium citrate synthesis method as reported previously 24. The bare monolithic silica capillary column was prepared according to the procedures described in the previous literature 30. A solution of 10% v/v MPTMS in toluene was passed through the activated bare monolithic silica capillary column and made to react at 110°C in the drying oven for 1 h; this step was repeated four times.…”