Nitrogen dozen carbon quantum dots as one dual function sensing platform for electrochemical and fluorescent detecting ascorbic acid

A novel amine-modified carbon quantum dots (NH 2 -CQDs), which can act as a dual-detection probe for the ascorbic acid (AA) response, was synthesized. The product was obtained via facile and green hydrothermal carbonization of L-histidine. The high nitrogen to carbon ratio of L-histidine warrants a high nitrogen content of these CQDs, and thus to have more free electron pairs. This results in good electron transport capability. The NH 2 -CQDs with an average diameter of 3.67 ± 0.78 nm display blue fluorescence, with excitation/emission maxima at 340/420 nm, and a quantum yield of 15.9%. The fluorescence can be quenched by AA. Moreover, the NH 2 -CQDs can selectively detect AA with electrochemical detection. On the basis of the electrochemical and fluorescent properties of the NH 2 -CQDs, the electrochemistry method and fluorescence analysis for the detection of AA with a detection limit of 2.7 μM and 57 nM are developed. This finding may provide a dual-detection platform, which can be used as a potential candidate for more selective to detect AA in pharmaceuticals, clinics, and food industries. Graphical abstract Schematic representation of the synthesis strategy of amine-modified carbon quantum dots (NH 2 -CQDs) and their electrochemical and fluorescent response to ascorbic acid (AA).