基于分子印迹整体柱的在线固相萃取-液相色谱联用测定奶粉中四环素类兽药残留

目的建立高交联结构的分子印迹整体柱(molecularly imprinted polymer monolithic column,MIP-MC)制备方法,利用在线固相萃取与液相色谱联用技术检测奶粉样品中四环素类兽药残留。方法在不锈钢色谱柱中,以土霉素为模板,甲基丙烯酸和甲基丙烯酸羟乙酯为功能单体,乙二醇二甲基丙烯酸酯和双季戊四醇六丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,在丙酮-甲醇-十二醇混合溶剂中,制备了分子印迹整体柱。将整体柱与液相色谱联用,在线固相萃取奶粉中的四环素类兽药残留。结果在最佳在线固相萃取条件下,获得了较高的富集因子(19.3)和净化效果。四环素类在0.05、0.25和0.5 mg/kg 3个加标水平下,回收率为84.2%~103.4%,相对标准偏差为1.37%~4.87%,方法检出限(S/N=3)和定量限(S/N=10)分别为8.48~11.74?g/kg和28.24~39.09?g/kg。结论该在线固相萃取方法简单快速、灵敏性高、选择性好,适用于奶粉中四环素类抗生素残留的测定。

Determination of tetracycline veterinary drug residues in milk powder by on-line solid phase extraction coupled with high performance liquid chromatography with molecularly imprinted monolithic column

Objective A preparation method of molecularly imprinted polymer monolithic column (MIP-MC) with the high cross-linking structures was developed for selective was prepared in a stainless-steel chromatographic column for the determination of tetracyclines residues in milk powder by on-line separation and enrichment technique. Methods The MIP-MC was prepared in a stainless steel column using oxytetracycline as the template, methacrylic acid and hydroxyethyl methacrylate as functional monomers, ethylene glycol dimethacrylate and dipentaerythritol hexaacrylate as the cross-linking agent, azobisisobutyronitrile as initiator, acetone-methanol-dodecanol as porogenic solvent. The obtained monolith was applied to the determination of tetracycline drugs in milk powder by on-line solid-phase extraction coupling with HPLC. Results An en-richment factor of 19.3 along with a good sample clean-up effect was obtained under optimum on-line solid phase extraction conditions. The average recoveries of tetracyclines in milk powder spiked milk at 0.05, 0.2 and 0.5 mg/kg were in the range of 84.2%~103.4% with the precision of 1.37~4.87%. The limits of detection (S/N=3) and quantitation (S/N=10) of the proposed method were 8.48~11.74 mg/kg and 28.24~39.09 mg/kg, respectively. Conclusion The on-line solid phase extraction method is simple, rapid, highly sensitive, and good selectivity for the determination of tetracyclines antibiotics in milk powder.