Separation of acidic and basic compounds in capillary electrochromatography with polymethacrylate-based monolithic columns

CEC with new monolithic stationary phase based on a fluorinated monomer, trifluoroethyl methacrylate

“…This plot showed that simultaneous separation was possible in the studied range of ACN/buffer ratio except for 3-nitrophenol and 2,4-dinitrophenol. The use of poly(TFEM-co-EDMA) monolith allowed the simultaneous separation of aniline and benzoic acid derivatives by a single run and by using a lower ACN concentration in the mobile phase with respect to the similar electrochromatographic separations [56]. The effect of linear velocity on both the TPN and the plate height of the poly(TFEM-co-EDMA) monolith is shown on the same plot in Fig.…”

“…Benzoic acids Anilines The average plate numbers between 177 000 and 210 000 plates/m were found for poly(BMA-co-EDMA) monolithic stationary phases with sulfonic acid functionalities for thiourea [56,57].The monolithic stationary phase prepared by the in situ copolymerization of pentaerythritol diacrylate monostearate and AMPS was evaluated in the electrochromatographic separation of small neutral and charged species and the column efficiencies up to 210 000 plates/m were obtained [31]. The column efficiencies approximately 300 000 plates/m were also reported for hexyl methacrylate-or butyl acrylate-lauryl acrylate-based monoliths with optimized EOF conditions in the separation of polycyclic aromatic hydrocarbons [58,59].…”

CEC separation of heterocyclic amines using methacrylate monolithic columns

“…5) because they were neutral under these conditions and the driven flow was only the EOF. Although several authors have taken advantage of the hydrophobic interactions with the butyl chains of the methacrylate structure to separate basic compounds [38], in our case these interactions seem to be not selective enough to separate the compounds. In order to test the occurrence of both electrophoretic mobility and interactions with the monolith, we have performed the separation of HAs in CZE using a fused-silica capillary and CEC under the same conditions (30 cm total capillary length, 80 mM formic acid/ammonium formate pH 2.8, 10% MeOH).…”

“…Although some authors have stated that basic compounds can be eluted with serious peak tailing when using these columns [15], other groups have used them for the separation of anilines [9,28,37,38], nucleosides [36] and other amino compounds [38,39], without observing important distortions in peak shape, mainly when working with basic mobile phases. For HAs analysis, the electrochromatographic separation was performed in normal flow by means of the application of a cathodic polarity.…”

Recent advances in capillary electrophoresis and capillary electrochromatography of pollutants

“…This stationary phase was used for ion-exchange CEC of inorganic anions in a 75-mm ID capillary with Tris/perchlorate electrolyte and direct UV detection at 195 nm. Methacrylate-based monolithic columns with EOF or very weak EOF prepared by in situ copolymerization in the presence of a porogen in fusedsilica capillaries pretreated with a bifunctional reagent were reported by Ping et al [134]. Satisfactory separations of acidic and basic compounds on the column with EOF at either low or high pH were achieved, respectively.…”