Abstract: AccuBlue fluorescent dye displays only weak fluorescence when being free or coexisting with single-stranded DNA, but significantly enhanced fluorescent signals when coexisting with double-stranded DNA. In this study, a novel fluorescence method for enrofloxacin detection was established based on the reaction between AccuBlue fluorescent dye and a nucleic acid aptamer. The optimal detection conditions were as follows: in a buffer solution at pH 8.5, the double strand was incubated for 10 min, and the fluorescent dye was allowed 6 min to recognize the double strand. Results indicated that the calibration curve was linear in the concentration range of 20–1 000 μg/L. Validation of the method yielded a limit of detection (LOD) (RSN ≥ 3) of 9.96 μg/L and a limit of quantification (LOQ) (RSN ≥ 10) of 29.97 μg/kg. The intra- and inter-plate variation coefficients were in the ranges of 4.97%–9.31% and 5.83%–10.96%, respectively. Recoveries measured for the extraction of enrofloxacin spiked into milk powder, shrimp and beef were between 76.54% and 98.79%. The method developed proved to be specific, stable, and repeatable, and could be easily implemented for rapid detection of enrofloxacin in real samples.

Key words: enrofloxacin; aptamer; fluorescent dye; rapid detection