Verdon E, Couedor P
Ministère de l'Agriculture et de la Pêche, Centre National d'Etude Vétérinaire et Alimentaire, Laboratoire des Médicaments Vétérinaires, Javené, Fougères, France.
J Chromatogr B Biomed Sci Appl. 1998 Jan 23;705(1):71-8. doi: 10.1016/s0378-4347(97)00494-5.
A high-performance liquid chromatographic method has been developed for the determination of isoxazolylpenicillins (oxacillin, cloxacillin and dicloxacillin) residues in milk. This method involves extraction of the penicillins from milk with phosphate buffer pH 8, deproteinization by acidification with sulfuric acid followed by cleanup and concentration on a C18 solid-phase extraction column and reaction with 1,2,4-triazole and mercury(II) chloride solution pH 9.0 at 65 degrees C. The derivatized compound is eluted on a C8 column with a mobile phase containing acetonitrile, methanol and phosphate buffer (pH 6.5, 0.1 mol l(-1)) loaded with sodium thiosulfate and ion-pairing tetrabutylammonium hydrogenosulphate. The detection limit of the method is 2 microg l(-1) for oxacillin, 3 microg l(-1) for cloxacillin and 5 microg l(-1) for dicloxacillin in milk and the three penicillins have been quantified down to 15 microg l(-1) in line with the EU criteria of the directive No. 93/256/EEC.
已开发出一种高效液相色谱法，用于测定牛奶中异恶唑基青霉素（苯唑西林、氯唑西林和双氯西林）的残留量。该方法包括用pH 8的磷酸盐缓冲液从牛奶中提取青霉素，用硫酸酸化进行脱蛋白处理，然后在C18固相萃取柱上进行净化和浓缩，并在65℃下与1,2,4-三唑和pH 9.0的氯化汞（II）溶液反应。衍生化后的化合物在C8柱上用含有乙腈、甲醇和加载了硫代硫酸钠及离子对试剂硫酸氢四丁铵的磷酸盐缓冲液（pH 6.5，0.1 mol l(-1)）作为流动相进行洗脱。该方法对牛奶中苯唑西林的检测限为2 μg l(-1)，氯唑西林为3 μg l(-1)，双氯西林为5 μg l(-1)，并且这三种青霉素按照欧盟第93/256/EEC号指令的标准已定量至15 μg l(-1)。
