A novel fluorescence enhancement probe based on L-Cystine modified copper nanoclusters for the detection of 2,4,6-trinitrotoluene

The rapid development of fluorescent nanomaterials has broadened a new horizon for the design of easy-to-use and sensitive sensors. Herein, the stable, water-soluble and fluorescent L-Cystine modified copper nanoclusters (CuNCs) were prepared via size-focusing etching method. The maximum emission wavelength of the obtained CuNCs was 500   nm with an excitation wavelength of 396   nm. The as-prepared CuNCs can only emit faint light when dispersed in aqueous solution, but generate obvious fluorescence intensity enhancement after adding specific amount of 2,4,6-trinitrotoluene (TNT). Under the optimal conditions, the CuNCs were adopted as an effective fluorescence probe for the detection of trace TNT through fluorescence “turn-on” mode for the first time. The calibration curve of TNT was linear up to 4.8   μM, with a detection limit of 9.1   nM.