Bailón-Pérez M Isabel, García-Campaña Ana M, Cruces-Blanco Carmen, Del Olmo Iruela Monsalud
Department of Analytical Chemistry, Faculty of Sciences, Campus Fuentenueva, University of Granada, Granada, Spain.
Electrophoresis. 2007 Nov;28(22):4082-90. doi: 10.1002/elps.200700305.
A method for the simultaneous determination of eight beta-lactam antibiotics (nafcillin, cloxacillin, oxacillin, dicloxacillin, ampicillin, amoxicillin, and penicillin G) in fortified milk samples of different origins has been proposed by using CZE with diode-array detection (CZE-DAD). Optimum separation was obtained on a 64.5 cm x 75 microm bubble cell capillary using 175 mM Tris buffer with 20% ethanol at pH 8.0. Methylparaben has been used as an internal standard (IS). Taking into account the lack of sensitivity of the UV-Vis detection, a solvent extraction/SPE method was applied for off-line preconcentration and sample cleanup, and also an on-line preconcentration methodology, such as large-volume sample stacking (LVSS) with polarity switching, was developed, providing LODs ranging from 2 to 10 microg/L. The method permits the quantification of these residues below the levels established in milk by the EU Regulation. Satisfactory recoveries ranging from 86 to 93% were also obtained in milk samples of different origins.
已提出一种使用带有二极管阵列检测的毛细管区带电泳(CZE-DAD)同时测定不同来源加标牛奶样品中八种β-内酰胺抗生素(萘夫西林、氯唑西林、苯唑西林、双氯西林、氨苄西林、阿莫西林和青霉素G)的方法。在一根64.5 cm×75 μm气泡池毛细管上,使用pH 8.0的含20%乙醇的175 mM Tris缓冲液可实现最佳分离。对羟基苯甲酸甲酯用作内标(IS)。考虑到紫外-可见检测灵敏度不足,采用了溶剂萃取/固相萃取方法进行离线预浓缩和样品净化,还开发了一种在线预浓缩方法,如带极性切换的大体积样品堆积(LVSS),检测限范围为2至10 μg/L。该方法能够对这些残留量进行定量,且低于欧盟法规规定的牛奶中残留量水平。在不同来源的牛奶样品中也获得了86%至93%的满意回收率。