Facile and sensitive detection of norfloxacin in animal-derived foods using immuno-personal glucose meter

Norfloxacin (NOR) is a type of fluoroquinolone broad spectrum antimicrobial drug capable of treating bacterial infections leading to adverse reactions and a reduction in the efficiency for treating infection in humans. To ensure consumer safety, a facile and sensitive immunoassay using personal glucose meter (PGM) was developed for the detection of NOR in animal-derived foods in this study. In which, invertase, an enzyme that could catalyze the hydrolysis of sucrose into glucose, was conjugated with anti-NOR monoclonal antibody with the help of colloidal gold, and named as signal probes. NOR-BSA functionalized magnetic beads were used as sensing probes to compete with NOR for binding to signal probes. Based on a competitive immunoassay format, a facile method to detect NOR was performed using PGM as signal transducer. The detection limit for NOR in standard solution was 0.5 ng mL(-1) with a wide linear range of 0.5-500 ng mL(-1) (R-2 = 0.9905). For specificity analysis, the data obtained showed no obvious PGM signal changes with other fluoroquinolones except ciprofloxacin (CIP) and enrofloxacin (ENR), indicating this method could be applied for the detection of three kinds of fluoroquinolones (NOR, CIP and ENR). The recoveries of NOR in spiked animal-derived foods ranged from 73.14 to 137.37%. Besides, the results obtained by the proposed method showed high agreement with commercial ELISA kits. In conclusion, the proposed immuno-PGM assay provided an alternative method for facile and sensitive detection of NOR in animal-derived foods.