Polymerised bicontinuous microemulsions as stationary phases for capillary electrochromatography

Abstract

Polymerisation of bicontinuous microemulsions yields porous monolithic structures with well defined pore sizes that are potentially suitable for use as stationary phases for capillary electrochromatography (CEC). Avariety of pore sizes can be achieved by altering the composition of the microemulsion, which typically consists of butyl methacrylate (BMA) and ethylene glycol dimethacrylate (EGDMA) as the polymerisable oil phase. The aqueous phase consists of water, a surfactant (sodium dodecyl sulphate, SDS) and a co-surfactant (1-propanol). 2-acrylamido-2-methyl-l-propane sulfonic acid (AMPS) is also added to provide charges along the polymer backbone to allow electroosmotic flow (EOF) to occur. SEM analysis shows that in-situ polymerisation yields a monolithic structure with a porous topography. Investigations have shown that these monoliths are easy to prepare, robust and suitable for the separation of phthalates. They generate higher linear velocities than are achieved using the silica based HPLC packings normally used for CEC.

Recent developments in the field of monolithic stationary phases for capillary electrochromatography

“…Another less common approach involving in-situ polymerization of bicontinuous microemulsions was introduced by Cameron et al [115]. Recently, they extended their study and prepared monolithic poly(butyl methacrylate-co-ethylene dimethacrylate-co-2-acrylamido-2-methyl-1-propanesulfonic acid) columns for CEC using mixtures containing varying percentages of surfactant and 1-propanol [116].…”

Development and application of polymeric monolithic stationary phases for capillary electrochromatography

“…In addition to providing permeability, the porous structure also accelerates mass transfer within the separation medium as a result of convection [66], since all of the mobile phase must flow through the pores [67]. The importance of this fact has meant a rapid increase in the number of studies directly assessing the effect of pore size of the monolithic CEC media [33,44,50,61,[68][69][70][71][72]. However, these still represent a relatively small subset of the literature in this field.…”

“…Cameron et al also described the preparation of monolithic stationary phases for CEC from the polymerization of bicontinuous microemulsions [72]. The porous structure was examined by both mercury intrusion porosimetry and SEM and this process was shown to produce monoliths with narrow pore size distribution.…”

Recent advances in polymeric monolithic stationary phases for electrochromatography in capillaries and chips

“…Cameron et al [10] have reported the polymerization of bicontinuous microemulsions of BMA and the cross-linker EDMA as the polymerizable oil phase in the presence of an aqueous phase which typically consisted of water, a surfactant (SDS), a co-surfactant (1-propanol), and AMPS. 1-Propanol was added to form an optically homogenous solution and 2,2'-azo-bis(isobutyronitrile) (AIBN) was used to initiate the polymerization.…”