Spectrofluorimetric determination of ofloxacin in milk with N-(9-fluorenylmethyloxycarbonyl)-l-alanine

•Enhancing fluorescence was produced by F-Ala interacting with OFL.•The fluorescence of OFL–F-Ala was controlled by pH and solvents.•High selectivity and sensitivity were obtained by the new method.•The LOD of OFL was 0.01 μg mL−1 in milk.

It was found that N-(9-fluorenylmethyloxycarbonyl)-l-alanine (F-Ala) could interact with ofloxacin (OFL) and enhance the fluorescence of OFL, which could be used to set up a new fluorescence spectrophotometry method to detect OFL without isolation procedure. The experimental conditions were discussed and when MeOH was used as solvent, 0.001 μg mL−1 of OFL could be detected. For making the method could be used easily in milk samples, MeOH/H2O (v/v, 4:1, pH 4.1) was used as the optimal solvent condition, the limit of quantification of OFL could be reached 0.01 μg mL−1 in milk samples with recovery more than 88% at least.

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