基于限进介质-磁性微球的磁分散萃取-液相色谱法同时检测牛奶中四环素类药物残留

Simultaneous determination of tetracyclines residues in milk using magnetic dispersion extraction-liquid chromatography based on restricted access media-magnetic microsphere

目的：建立了一种集净化和富集为一体的限进介质磁性微球(RAM-MMs)制备方法和磁分散萃取牛奶中四环素类抗生素方法。方法采用悬浮聚合法,制备了表面亲水的磁性高分子微球。以牛奶为原料,样品经三氯乙酸和Na2EDTA-McIlvaine缓冲溶液提取,磁性微球净化富集后,用C18色谱柱分离,以甲醇：乙腈：10 mmol/L草酸(5：25：70, v：v：v)为流动相进行检测,外标法定量。结果在最佳条件下,获得了较好的净化效果和较高的富集因子(13.2)。在0.1、0.2、0.5 mg/kg三个加标水平下,此方法回收率为76.4%~95.84%,相对标准偏差为2.72%~6.81%,方法检出限(S/N=3)和定量限(S/N=10)分别为5.71~11.18μg/kg和19.02~37.28μg/kg。结论该方法简便快速、灵敏可靠、经济有效,适用于原奶中四环素类抗生素残留的测定。

Objective A novel synthesis method of restricted access media-magnetic microspheres (RAM-MMs) with enrichment and clean-up effect was developed for magnetic dispersion extraction (MDE) of te-tracyclines residues in milk. Methods The surface hydrophilic magnetic polymer microspheres were prepared by suspension polymerization. Tetracyclines were extracted from milk samples with trichloroacetic acid and Na2EDTA-McIlvaine buffer solution, and then detected by HPLC-UV with external standard method using me-thanol:acetonitrile:10 mmol/L oxalic acid solution (5:25:70, v:v:v) as mobile phase after being cleaned up with RAM-MMs. Results An enrichment factor of 13.2 along with a good sample clean-up was obtained under the optimized conditions. The average recoveries of three tetracyclines antibiotics spiked milk at 0.1, 0.2 mg/kg and 0.5 mg/kg were in the range of 76.4%～95.84%with the precision of 2.72%～6.81%. The limits of detection (S/N=3) and quantitation (S/N=10) of the proposed method were in a range of 5.71～11.18μg/kg and 19.02～37.28μg/kg, respectively. Conclusion This method is simple and fast, and its sensitivity, accuracy and precision can satisfy the requirement of tetracyclines residue analysis in milk.