Analyses of sulfonamide antibiotics by CEC using poly(divinylbenzene-1-octadecene-vinylbenzyl trimethyl ammonium chloride) monolithic columns

In this study, a series of novel polymeric monolithic columns prepared by single-step in situ copolymerization of 1-octadecene (OD), divinylbenzene (DVB) and/or styrene (S), were developed as separation columns for the sulfonamide analyses. On the CEC method, the composition of monomer mixtures (i.e. the ratio of S versus OD), content of charge-bearing monomer (vinylbenzyl trimethylammonium chloride) and volume fraction ratio of ACN in the mobile phase, was found to be the predominant influences for sulfonamide separation. Furthermore, an online sample concentration step, field-amplified sample injection, was used to enhance the detection sensitivity of sulfonamides. Sample matrix's pH had a significant effect on the sulfonamide sensitivity. For the eight sulfonamides, the proposed poly(DVB-OD) monolithic stationary phase coupled with field-amplified sample injection step could achieve a reproducible baseline separation within 15 min and LODs in the range of 8.1-28.2 mu g/L.