Preparation of a mixed stir bar for sorptive extraction based on monolithic material for the extraction of quinolones from wastewater.

In this study, a novel mixed mode monolithic material was prepared and acted as the SBSE coating. The monolithic material was prepared by in situ copolymerization of methacrylic acid-3-sulfopropyl ester potassium salt (MASE) and divinylbenzene (DB) in the presence of a porogen solvent containing cyclohexanol, 1-dodecanol, and water with azobisisobutyronitrile as initiator. The influences of the contents of the porogen solvent and monomer in the polymerization mixture on the extraction performance were investigated thoroughly. Several characteristic techniques, such as elemental analysis, scanning electron microscopy and infrared spectroscopy were used to characterize the monolithic material. To achieve optimum extraction performance for quinolones, several parameters, including pH value, desorption solvent, ionic strength in sample matrix, extraction and desorption time were investigated. The results show that under the optimized experimental conditions, the method has good sensitivity, linearity, simplicity and low cost. The extraction performance of present method to the target compounds was compared with commercial SBSE which using polydimethylsiloxane as coating and other SBSEs which based on monolithic materials. The comparative results indicate that present SBSE can extract the analytes more effectively than other SBSEs because both ion-exchange and hydrophobic interactions contribute to the extraction of quinolones. Copyright 2009 Elsevier B.V. All rights reserved.