N-doped molybdenum oxide quantum dots as fluorescent probes for the quantitative detection of copper ions in environmental samples.

A novel, sensitive, and selective fluorescence sensor based on N-doped Mo oxide quantum dots (N-MoOx QDs) was fabricated for the detection of Cu ions in water. The presence of Cu induced dynamic fluorescence quenching of the N-MoOx QDs. The sensing conditions were optimized to enhance selectivity and sensitivity. Under optimal conditions, the linear relationship between fluorescence response at 408 nm and Cu concentration was determined. The linear range of this relationship was 1-100 μM. The limits of detection (LOD) and quantitation (LOQ) for Cu were 0.78 μM and 2.34 μM, respectively. The method was successfully applied to detect Cu in water samples with satisfactory sample recovery rates from 91.7 to 116.4%. The sensor exhibits high selectivity toward Cu, making it useful for environmental sample monitoring.