A reversible pyrene-based fluorescent probe for visual detection of cysteine in food samples

A reversible fluorescent probe Pyr-1 was developed by integrating pyrene and oxime functional groups and applied for visual detection of Cysteine (Cys). By featuring three binding sites, Pyr-1 exhibited selective fluo-rescence quenching response towards Fe3+ through the formation of 1:1 coordination complex. The ensemble Pyr-1-Fe3 thorn was further applied to detect Cys. Among the various test species, Cys induced unique fluorescence enhancement through the decomplexation process. The detection of Cys exhibited a fluorescence turn-off-on phenomenon within 50 s and reversible cycle performed up to at least 32 times. The detection limit was calculated as 0.446 mu M. Due to the excellent stability in wide pH range (2-11), Pyr-1-Fe3 thorn was successfully applied in detection of Cys in diverse food samples. In practical applications, an obvious fluorescent color dif-ference was observed on paper-based device modified by Pyr-1-Fe3 thorn , which was convenient and could be used for on-site evaluation of Cys in food samples.

Automated summary

A reversible fluorescent probe Pyr-1 was developed for visual detection of Cysteine (Cys) by integrating pyrene and oxime functional groups. Pyr-1 exhibited selective fluorescence quenching response towards Fe3+ and the ensemble Pyr-1-Fe3 complex was applied for Cys detection. Cys induced unique fluorescence enhancement through the decomplexation process.