Doping a novel controlled/“living” radical for the polymerization of a lauryl methacrylate monolithic column for improving column efficiency

Abstract

The preparation of a lauryl methacrylate (LMA) monolithic column for CEC by reversible addition–fragmentation chain transfer polymerization has been investigated. s,s-2(α,α’-Methyl-α′′-acetic acid)3-thiocarbonate (TTC1) was synthesized and added into the LMA monolithic column preparation as a chain transfer agent. At the same time, the preparation was compared with LMA-based monolith columns which were thermally polymerized without TTC1. SEM and pore size measurements showed that reversible addition–fragmentation chain transfer polymerization results in a more uniform polymer particle pore size, relatively narrower pore size distribution and larger surface area. The two kinds of monoliths had median pore diameters of 703 nm and 950 nm with pore volumes of 13.22 cm³ g⁻¹ and 8.31 cm³ g⁻¹, respectively. The influence of the TTC1 amount and porogenic solvent composition on the physical and electrochromatographic properties of the LMA-based monolithic columns was also evaluated by capillary electrochromatography (CEC). Under the optimum conditions, an H_min value of 7.39 μm for naphthalene was achieved. The relative standard deviations (RSDs) of column-to-column (n = 9), run-to-run (n = 5) and day-to-day (n = 3) reproducibility were lower than 4.8%.