Determination of flumioxazin residue in food samples through a sensitive fluorescent sensor based on click chemistry

• A simple fluorescent sensor for flumioxazin determination had been developed.
• The sensor combined the merits of click chemistry and fluorescent.
• The sensor owns the characters of high selectivity and stability.
• The sensor has been applied to detect flumioxazin residua in vegetable samples.

A sensitive and selective fluorescent sensor for flumioxazin was designed based on the formation of strong fluorescence compound (1,2,3-triazole compounds) via the reaction of the alkynyl group in flumioxazin with 3-azido-7-hydroxycoumarin, a weak-fluorescent compound, through the Cu+-catalysed azide–alkyne cycloaddition (CuAAC) reaction. The fluorescence increase factor (represented by F/F0) of the system exhibited a good linear relationship with the concentrations of flumioxazin in the range of 0.25–6.0 μg/L with a detection limit of 0.18 μg/L (S/N = 3). Also, the proposed fluorescent sensor demonstrated good selectivity for flumioxazin assay even in the presence of high concentration of other pesticides. Based on such high sensitivity and selectivity, the proposed fluorescent sensor has been applied to test the flumioxazin residue in some vegetable and water samples with satisfied results.