A rapid, specific, and sensitive method has been developed using molecularly imprinted polymers (MIPs) as solid-phase extraction sorbents for extraction of trace tetracycline antibiotics (TCs) in foodstuffs. MIPs were prepared by precipitation polymerization using tetracycline as the template. Under the optimal condition, the imprinting factors for MIPs were 4.1 (oxytetracycline), 7.0 (tetracycline), 7.4 (chlortetracycline), 7.7 (doxycycline), respectively. Furthermore, the performance of MIPs as solid-phase extraction sorbents was evaluated and high extraction efficiency of molecularly imprinted solid-phase extraction (MISPE) procedure was demonstrated. Compared with commercial sorbents, MISPE gave a better cleanup efficiency than C18 cartridge and a higher recovery than Oasis HLB cartridge. Finally, the method of liquid chromatography-tandem mass spectrometry coupled with molecular-imprinted solid-phase extraction was validated in real samples including lobster, duck, honey, and egg. The spiked recoveries of TCs ranged from 94.51% to 103.0%. The limits of detection were in the range of 0.1-0.3 microg kg(-1).

A new method is developed for the determination of acrylamide in starch-based foods. The method included the extraction of acrylamide with water, defatting with hexane, derivatization with potassium bromate (KBrO(3)) and potassium bromide (KBr), liquid-liquid extraction with ethyl acetate-hexane (4:1), and concentration. The final analyte (2-bromopropenamide, 2-BPA) is analyzed by high-performance liquid chromatography coupled with diode array detection for quantification and by gas chromatography coupled to mass spectrometry for confirmation. The chromatographic analysis is performed on an ODS-3 C(18) column, and good retention and peak response of acrylamide are achieved under the optimal conditions. The limit of detection and quantitation are estimated to be 15 and 50 μg/kg, respectively. The recoveries of acrylamide from the commercial samples are spiked at levels of 50-1000 μg/kg, and range between 89.6 and 102.0%. These results show that this method should be regarded as a new, low-cost, and robust alternative for conventional investigation of acrylamide.

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Group-selective molecularly imprinted polymers (MIPs) were synthesized from three kinds of sulfonamides (SAs) and three different functional monomers, with those employing sulfamerazine (SMR) and 2-vinylpyridine (2-Vpy) found to be optimal. The BET test, static adsorption and solidphase extraction (SPE) recovery indicate that the MIPs exhibit strong affinity toward SAs in aqueous solution. Therefore they were used for the quantitative analysis of five SAs in wastewater from treatment plants by off-line SPE coupled to reversed-phase HPLC/DAD. The recoveries and relative standard deviation (RSD) of the molecularly imprinted solid-phase extraction (MISPE) method are 84.1-98.6% and 1.5 to 7.4% in wastewater. The limit of detection (LOD) and the enrichment factor (EF) for SAs were 4.09-19.29 ng L À1 and 411-506 respectively. Five SAs analytes were detected in influents, with residues still remaining in effluents in the range of 29.30-1389.80 ng L À1 .

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