Kobra Zavar Mousavi - Department of Chemistry, Faculty of Science, Tarbiat Modares University, Tehran, Iran
Babak karimi - Department of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan, Iran
Shahram Seidi - Department of Analytical Chemistry, K.N. Toosi University of Technology, Tehran, Iran
Yadollah Yamini - Department of Chemistry, Faculty of Science, Tarbiat Modares University, Tehran, Iran

Microextraction by packed sorbent (MEPS) was adopted as a simple, fast, and on-line sample preparation technique after its introduction in 2004 by Abdel-Rehim [1]. MEPS is a miniaturization of the conventional SPE and very promising technique for sample preparation. Sorbent type is a core aspect of MEPS. MEPS selectivity depends on sorbent type because the analytes are retained by the sorptive materials via different reversible interactions (hydrophobic, polar, and ionic) [2].The present work focuses on the development of imidazolium-based bifunctional periodic mesoporous organosilicas (BFPMO) nanostructure as novel sorbent for MEPS. Here, it is believed the integrating of PMO and IL providing new organic–inorganic hybrid materials that can open novel branch toward to MEPS technique. For this purpose, chlorophenoxy acid (CPA) herbicides were tested as model compounds in aqueous matrices at a trace level. The factors that influenced on the extraction efficiency of CPAs including the number of draw/eject cycles of the sample, draw/eject flow rate, the washing volume of water, the nature of the eluting solvent and ionic strength were investigated and optimized. Finally, the proposed method was successfully applied to the analysis of trace CPAs in environmental samples.