Kantiani Lina, Farré Marinella, Sibum Martin, Postigo Cristina, López de Alda Miren, Barceló Damiá
Department of Environmental Chemistry, IDAEA-CSIC, c/Jordi Girona 18-26, 08034, Barcelona, Spain.
Anal Chem. 2009 Jun 1;81(11):4285-95. doi: 10.1021/ac9001386.
A fully automated method for the detection of beta-lactam antibiotics, including six penicillins (amoxicillin, ampicillin, cloxacillin, dicloxacillin, oxacillin, and penicillin G) and four cephalosporins (cefazolin, ceftiofur, cefoperazone, and cefalexin) in bovine milk samples has been developed. The outlined method is based on online solid-phase extraction-liquid chromatography/electrospray-tandem mass spectrometry (SPE-LC/ESI-MS-MS). Target compounds were concentrated from 500 microL of centrifuged milk samples using an online SPE procedure with C18 HD cartridges. Target analytes were eluted with a gradient mobile phase (water + 0.1% formic acid/methanol + 0.1% formic acid) at a flow rate of 0.7 mL/min. Chromatographic separation was achieved within 10 min using a C-12 reversed phase analytical column. For unequivocal identification and confirmation, two multiple reaction monitoring (MRM) transitions were acquired for each analyte in the positive electrospray ionization mode (ESI(+)). Method limits of detection (LODs) in milk were well below the maximum residue limits (MRLs) set by the European Union for all compounds. Limits of quantification in milk were between 0.09 ng/mL and 1.44 ng/mL. The developed method was validated according to EU's requirements, and accuracy results ranged from 80 to 116%. Finally, the method was applied to the analysis of twenty real samples previously screened by the inhibition of microbial growth test Eclipse 100. This new developed method offers high sensitivity and accuracy of results, minimum sample pre-treatment, and uses for the first time an automated online SPE offering a high throughput analysis. Because of all these characteristics, the proposed method is applicable and could be deemed necessary within the field of food control and safety.
已开发出一种全自动方法，用于检测牛奶样品中的β-内酰胺类抗生素，包括六种青霉素（阿莫西林、氨苄西林、氯唑西林、双氯西林、苯唑西林和青霉素G）和四种头孢菌素（头孢唑林、头孢噻呋、头孢哌酮和头孢氨苄）。所述方法基于在线固相萃取-液相色谱/电喷雾串联质谱法（SPE-LC/ESI-MS-MS）。使用配备C18 HD柱的在线SPE程序，从500微升离心后的牛奶样品中富集目标化合物。目标分析物用梯度流动相（水+0.1%甲酸/甲醇+0.1%甲酸）以0.7毫升/分钟的流速洗脱。使用C-12反相分析柱在10分钟内实现色谱分离。为进行明确鉴定和确认，在正电喷雾电离模式（ESI(+)）下，对每种分析物采集两个多反应监测（MRM）跃迁。牛奶中的方法检测限（LOD）远低于欧盟为所有化合物设定的最大残留限量（MRL）。牛奶中的定量限在0.09纳克/毫升至1.44纳克/毫升之间。所开发的方法根据欧盟要求进行了验证，准确度结果在80%至116%之间。最后，该方法应用于对之前通过微生物生长抑制试验Eclipse 100筛选的20个实际样品的分析。这种新开发的方法具有高灵敏度和结果准确性、最少的样品预处理，并且首次使用自动化在线SPE实现高通量分析。由于所有这些特性，所提出的方法适用于食品控制和安全领域，并且可能被认为是必要的。
