A fluorescent probe constructed of water-soluble dual-element-doped carbon quantum dots for rapid and highly sensitive detection of Ag+

• An innovative N,S-CDs were synthesized by a rapid one-step hydrothermal method. • The obtained N,S-CDs had high quantum yield (36.8%) and good optical stability. • Selective detection of Ag + were achieved by fluorescent probe based on N,S-CDs. • The fluorescent probe is suitable for the detection of Ag + in actual water samples. Ag + , extensively used in our daily life, has caused serious harm to human health and ecological environment, so highly selective detection and accurate quantification of Ag + are critical. Herein, we report a novel water-soluble dual-element composite doped carbon quantum dots, N,S-CDs, then constructed them into fluorescent probes for Ag + detection. Carbon source ammonium citrate (AC) could achieve nitrogen doping without additional nitrogen source, inorganic sulfur source sodium thiosulfate was used for rapid sulfur doping, the N,S-CDs emitting dazzling blue fluorescence were obtained through a rapid hydrothermal process. The synthesized N,S-CDs had an average particle size of 3.25 nm, with high quantum yield (QY = 36.8%) and excitation-independent fluorescence properties. Under optimized conditions, the fluorescent probe constructed by N,S-CDs could detect Ag + with high sensitivity and fast response, showing a good piecewise linear relationship (0.1–700 μM). In addition, the fluorescent probe exhibited remarkable anti-interference ability and reusability, which is practical and feasible, and has broad application prospects in biological and environmental sample detection.