MacIntosh A I
Health and Welfare Canada, Bureau of Drug Research, Tunney's Pasture, Ottawa, Ontario, Canada.
J Assoc Off Anal Chem. 1990 Nov-Dec;73(6):880-2.
A liquid chromatographic (LC) method was developed for quantitative determination of cephapirin residues in milk that also resolved cephapirin from ampicillin, cloxacillin, and penicillin G. Diluted milk was passed through a C18 cartridge on which the cephapirin was adsorbed; then, interfering material was removed by washing with water and methylene chloride and cephapirin residues were eluted with methanol-acetonitrile (25 + 75). After drying, residues were dissolved in the mobile phase for injection. The LC system had an ultrasphere-ODS column with RP-18 Spheri-10 guard column and a UV detector with a 254 nm filter. The mobile phase was 85% sodium acetate (0.01M) and 15% methanol-acetonitrile (25 + 75) with a flow rate of 1 mL/min. Sensitivity was 20 ppb or less with a recovery of 61-80% in the range studied. Other beta-lactam antibiotics tested did not interfere with detection of cephapirin. Analysis of 30 samples of commercial homogenized milk obtained for a survey of antibiotics in consumer milk in Canada revealed no detectable cephapirin residues.
建立了一种液相色谱（LC）方法，用于定量测定牛奶中的头孢匹林残留量，该方法还能将头孢匹林与氨苄西林、氯唑西林和青霉素G分离。将稀释后的牛奶通过C18柱，头孢匹林吸附在该柱上；然后，用水和二氯甲烷洗涤除去干扰物质，并用甲醇 - 乙腈（25 + 75）洗脱头孢匹林残留。干燥后，将残留物溶解在流动相中进行进样。LC系统具有带RP - 18 Spheri - 10保护柱的超球ODS柱和带254 nm滤光片的紫外检测器。流动相为85%的醋酸钠（0.01M）和15%的甲醇 - 乙腈（25 + 75），流速为1 mL/min。在所研究的范围内，灵敏度为20 ppb或更低，回收率为61 - 80%。测试的其他β - 内酰胺类抗生素不干扰头孢匹林的检测。对从加拿大消费牛奶抗生素调查中获得的30份市售均质牛奶样品进行分析，未检测到头孢匹林残留。
