Institute of Food Chemistry, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany; School of Food Science and Technology, Jiangnan University, 214022 Wuxi, China.
J Chromatogr A. 2013 Oct 18;1312:143-51. doi: 10.1016/j.chroma.2013.09.006. Epub 2013 Sep 7.
A rapid and efficient method for preliminary screening of four tetracyclines (tetracycline, chlortetracycline, oxytetracycline, doxycline) and three fluoroquinolones (enrofloxacin, ciprofloxacin, marbofloxacin), mostly detected in milk, by high-performance thin-layer chromatography-fluorescence detection and electrospray ionization mass spectrometry (HPTLC-FLD-ESI/MS) is highlighted. The optimized separation of the target antibiotics on ethylenediamine tetraacetic acid modified silica gel plates showed marked benefits for screening purposes. Besides, selective and sensitive densitometry in fluorescence mode was established with excitation at 366nm for the tetracyclines, 300nm for enrofloxacin and ciprofloxacin, and 280nm for marbofloxacin. Limits of detection (LOD) and quantitation (LOQ) with 95% confidence were in the range of 12-25 and 45-95μg/kg, respectively, in milk samples. Recoveries of target antibiotics from milk samples spiked at three critical levels (50, 100 and 150μg/kg) ranged from 76% to 105%. More importantly, a mass selective detection (MSD) was established as additional tool for confirmatory purposes. Using the elution-head based TLC-MS interface, the optimized elution flow consisting of acetonitrile/ammonium formate buffer (9/1, v/v) at a rate of 0.3mL/min enabled time-dependent resolution of analytes from the major interfering compounds, thus circumventing serious ion suppression effects. The established MSD assay also offered high sensitivity (25μg/kg) for confirmation, meeting Commission Regulation (EU) No. 37/2010.
本文主要介绍了一种高效快速的方法，用于初步筛选牛奶中四种四环素（四环素、金霉素、土霉素、多西环素）和三种氟喹诺酮类药物（恩诺沙星、环丙沙星、马波沙星），该方法采用高效薄层色谱-荧光检测-电喷雾电离质谱法（HPTLC-FLD-ESI/MS）。在乙二胺四乙酸改性硅胶板上优化分离目标抗生素，对筛选工作有明显的好处。此外，在荧光模式下建立了选择性和灵敏的密度测定法，四环素的激发波长为 366nm，恩诺沙星和环丙沙星为 300nm，马波沙星为 280nm。在牛奶样品中，检测限（LOD）和定量限（LOQ）的置信度为 95%，范围分别为 12-25μg/kg 和 45-95μg/kg。在牛奶样品中，目标抗生素的回收率在三个关键水平（50、100 和 150μg/kg）的范围内为 76%-105%。更重要的是，建立了质量选择检测（MSD）作为确证目的的附加工具。使用基于洗脱头的 TLC-MS 接口，优化的洗脱流由乙腈/甲酸铵缓冲液（9/1，v/v）组成，流速为 0.3mL/min，使分析物与主要干扰化合物实现时间分离，从而避免严重的离子抑制效应。所建立的 MSD 测定法也具有很高的灵敏度（25μg/kg），符合欧盟委员会（EU）第 37/2010 号法规。
