Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457, China.
Anal Bioanal Chem. 2011 Oct;401(7):2291-9. doi: 10.1007/s00216-011-5329-0. Epub 2011 Aug 21.
A new molecularly imprinted polymer (MIP), selective for major metabolites of quinoxaline-1,4-dioxides was firstly prepared by combining surface molecular imprinting technique with the sol-gel process. Methyl-3-quinoxaline-2-carboxylic acid (MQCA) was used as template, 3-aminopropyltriethoxysilane as functional monomer, and tetraethoxysilicane as cross-linker. The MIP was characterized by Fourier transform infrared and evaluated through static adsorption experiments. The results indicated that MIP had high adsorption capacity, fast binding kinetics for MQCA, and the polymer showed a high degree of cross-reactivity for quinoxaline-2-carboxylic acid (QCA). The MIP was then applied as a selective sorbent in an online solid phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC). For a 50-mL sample solution, enrichment factors of 1,349 and 1,046 for QCA and MQCA, respectively, and limits of detection (S/N=3) of 0.8 and 2 ng L(-1) for QCA and MQCA, respectively, were obtained (corresponding to 0.02 and 0.04 ng g(-1) in solid samples for final 100 mL of sample solutions of 5 g of pork). The sample preparation protocol was simplified and only included one step extraction with acetonitrile (MeCN) after the release of target analytes through acidic hydrolysis without further sample cleanup. The new MIP-SPE-HPLC method was successfully applied to the quantification of trace QCA and MQCA in pork muscle with good recoveries ranging from 67% to 80% and RSD below 8%.
一种新型的分子印迹聚合物（MIP），对喹喔啉-1,4-二酮的主要代谢物具有选择性，首次通过将表面分子印迹技术与溶胶-凝胶过程相结合而制备。使用 3-甲基喹喔啉-2-羧酸（MQCA）作为模板，3-氨丙基三乙氧基硅烷作为功能单体，四乙氧基硅烷作为交联剂。通过傅里叶变换红外光谱对 MIP 进行了表征，并通过静态吸附实验进行了评价。结果表明，MIP 对 MQCA 具有高吸附容量、快速结合动力学，且聚合物对喹喔啉-2-羧酸（QCA）具有较高的交叉反应性。然后，MIP 被用作在线固相萃取（SPE）与高效液相色谱（HPLC）结合的选择性吸附剂。对于 50 mL 样品溶液，QCA 和 MQCA 的富集因子分别为 1,349 和 1,046，QCA 和 MQCA 的检测限（S/N=3）分别为 0.8 和 2 ng L(-1)（相当于 5 g 猪肉样品 100 mL 最终溶液中 0.02 和 0.04 ng g(-1)）。样品制备方案得到简化，仅包括在通过酸性水解释放目标分析物后用乙腈（MeCN）进行一步提取，无需进一步的样品净化。新的 MIP-SPE-HPLC 方法成功应用于猪肉中痕量 QCA 和 MQCA 的定量分析，回收率在 67%至 80%之间，RSD 低于 8%。
