One step hydrothermal synthesis of carbon nanodots to realize the fluorescence detection of picric acid in real samples

In this work, carbon nanodots were synthesized using grape skin as raw material by one step hydrothermal method under optimized experimental conditions. The carbon nanodots were characterized by TEM, fluorescence, UV, IR and XPS. The average particle size of the carbon particles was 4.0 ± 1.5 nm. When excited at 430 nm, the carbon nanodots showed strong green fluorescence of 522 nm which was dependent on the excitation wavelength. The fluorescence quantum yield reached 18.67%. Stability and anti-photobleaching properties were ideal. Picric acid quenched the fluorescence of the carbon nanodots in the phosphate buffer solution at pH = 7.4, and a method of high sensitivity and selectivity to detect picric acid was established. The linear range was 0.06-79.4 μM, the correlation coefficient was 0.998, and the detection limit was 10 nM (S/N = 3). The method was successfully applied to the detection of picric acid in real water samples. The recoveries fell in the range of 95.64%-104.2% and the RSD was 0.26%-0.74%.