A Magnetic Particle-Based Competitive Enzyme Immunoassay for Rapid Determination of Ciprofloxacin: A Potential Method for the General Detection of Fluoroquinolones

Abstract

Fluoroquinolones are effective antimicrobial agents, but their residues in food may cause serious health issues. Hence, it is necessary to develop a rapid and simple assay for fluoroquinolones. In this study, monoclonal antibodies against ciprofloxacin with broad specificity to fluoroquinolones were prepared. The newly developed magnetic particle-based competitive enzyme immunoassay was performed in a homogeneous sample, and ciprofloxacin was quantitatively detected in the range of 0.3–24.3 ng mL−1. The IC50 and LOD values of the method were 2.27 ng mL−1 and 0.25 ng mL−1. In chicken muscle, the recoveries of spiked ciprofloxacin at 8, 20, and 40 ng mL−1 were all higher than 79%. Additionally, the performance of the developed magnetic particle-based immunoassay exhibited an excellent correlation with commercial ELISA kits (r = 0.997). The anti-ciprofloxacin monoclonal antibodies provided high cross-reactivity with eight fluoroquinolones analogues: enrofloxacin (110.1%), sarafloxacin (99.7%), difloxacin (90.2%), danofloxacin (89.8%), norfloxacin (110.3%), lomefloxacin (65.2%), ofloxacin (75.1%), and flumequine (45.0%). This protocol provides an alternative immunoassay for ciprofloxacin with the advantages of simple separation, a homogeneous reaction, rapid detection (within 30 min), and stable results. Furthermore, it may be employed for the rapid general determination of fluoroquinolones in animal products.