Heller D N, Ngoh M A
FDA Center for Veterinary Medicine, Laurel, MD 20708, USA.
Rapid Commun Mass Spectrom. 1998;12(24):2031-40. doi: 10.1002/(SICI)1097-0231(19981230)12:24<2031::AID-RCM432>3.0.CO;2-8.
The feasibility of a technique to confirm the presence of residues from seven beta-lactam antibiotics in bovine milk has been demonstrated. The technique makes use of electrospray ionization and tandem ion trap mass spectrometry. Residues are first extracted from milk by reversed-phase solid phase extraction. Target analytes are separated by on-line reversed-phase liquid chromatography and ionized in the electrospray interface. The product ion mass spectra are acquired following collision-induced dissociation of protonated molecules. Confirmation is based on comparison of full scan spectra between unknowns and bona fide standards. The feasibility of this technique has been demonstrated for the six beta-lactams currently approved for use in lactating dairy cattle (penicillin G, ampicillin, amoxicillin, cloxacillin, cephapirin and ceftiofur) and a drug not approved for animal use, cefazolin. The technique has been applied to control milk fortified at 5 ng/mL of penicillin G and 10 ng/mL of the other six drugs.
已证明一种用于确认牛乳中七种β-内酰胺类抗生素残留的技术的可行性。该技术利用电喷雾电离和串联离子阱质谱法。残留首先通过反相固相萃取从牛奶中提取。目标分析物通过在线反相液相色谱分离，并在电喷雾接口中电离。在质子化分子发生碰撞诱导解离后获取产物离子质谱。确认基于未知物与真实标准品的全扫描光谱比较。该技术已证明对目前批准用于泌乳奶牛的六种β-内酰胺类抗生素（青霉素G、氨苄青霉素、阿莫西林、氯唑西林、头孢匹林和头孢噻呋）以及一种未批准用于动物的药物头孢唑林可行。该技术已应用于检测添加了5 ng/mL青霉素G和10 ng/mL其他六种药物的强化牛奶。
