title: Highly sensitive detection of five typical fluoroquinolones in low-fat milk by field-enhanced sample injection-based CE in bubble cell capillary.
abstract: Fluoroquinolones are a group of synthetic antibiotics with a broad activity spectrum against mycoplasma, Gram-positive, and Gram-negative bacteria. Due to the extensive use of fluoroquinolones in farming and veterinary science, there is a constant need in the analytical methods able to efficiently monitor their residues in food products of animal origin, regulated by Commission Regulation (European Union) no. 37/2010. Herein, field-enhanced sample injection for sample stacking prior the CZE separation was developed inside a bubble cell capillary for highly sensitive detection of five typical fluoroquinolones in bovine milk. Ethylenediamine was proposed as the main component of BGE for the antibiotics separation. The effect of BGE composition, injection parameters, and water plug length on the field-enhanced sample injection-based CE with UV detection was investigated. Under the optimized conditions, described field-enhanced sample injection-based CE-UV analysis of fluoroquinolones provides LODs varying from 0.4 to 1.3 ng/mL. These LOD values are much lower (from 460 to 1500 times) than those obtained by a conventional CE in a standard capillary without bubble cell. The developed method was finally applied for the analysis of fluoroquinolones in low-fat milk from a Swiss supermarket. Sample recovery values from 93.6 to 106.0% for different fluoroquinolones, and LODs from 0.7 to 2.5 μg/kg, were achieved. Moreover, the proposed ethylenediamine-based BGE as volatile and compatible with MS system, enabled the coupling of the field-enhanced sample injection-based CE with a recently introduced electrostatic spray ionization MS via an iontophoretic fraction collection interface for qualitative fluoroquinolones identification.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, China; Laboratoire d'Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Yan
authors.initials: Y
authors.lastname: Deng
authors.forename: Natalia
authors.initials: N
authors.lastname: Gasilova
authors.forename: Liang
authors.initials: L
authors.lastname: Qiao
authors.forename: Ying-Lin
authors.initials: YL
authors.lastname: Zhou
authors.forename: Xin-Xiang
authors.initials: XX
authors.lastname: Zhang
authors.forename: Hubert H
authors.initials: HH
authors.lastname: Girault
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis*; D002417:Cattle; D004350:Drug Residues / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000379:methods*; D024841:Fluoroquinolones / Q000032:analysis*; D057230:Limit of Detection; D016014:Linear Models; D008892:Milk / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones
keywords: Bubble cell capillary; CE-electrostatic spray ionization MS; Field-enhanced sample injection; Fluoroquinolones; Milk