Selectivity of two types of sulfadimidine-imprinted monolithic polymer-based fibers

Molecularly imprinted polymeric monolithic fiber is a new technique of solid-phase microextraction that focuses on selectivity. However, the inner mechanism of increasing the selectivity is not well understood. Here, a new approach to improve the selectivity is shown through controlling the surface of a molecular imprinted polymeric monolithic fiber. Sulfadimidine-imprinted polymeric monolithic fibers were fabricated using two kinds of molds, the polytetrafluoroethylene capillary and the silica capillary. A mixture of sulfadimidine, sulfamerazine, sulfadiazine, and sulfametoxypirydazine was used to test the selectivity of the fibers to sulfadimidine. This paper demonstrates that the extraction ratio for sulfadimidine in mixture is increased to more than 150% in sulfadimidine-imprinted polymeric monolithic fiber compared to nonimprinted polymeric monolithic fiber. The extraction ratio is increased to about 30% in sulfadimidine-imprinted polymeric monolithic fiber fabricated from silica capillary than in the counterpart from nonimprinted polymeric monolithic fiber. The sulfadimidine-imprinted polymeric monolithic fibers were also applied to extract standard mixtures spiked into Pearl River water and milk. The results indicated that polytetrafluoroethylene-sulfadimidine imprinted polymeric monolithic fiber showed highest selectivity to sulfadimidine in complex samples.