A water-soluble near-infrared fluorescent probe for specific Pd²⁺ detection

Palladium (Pd) is widely used in chemistry, biology, environmental science etc., and Pd²⁺ is the most plenitudinous oxidation state of the Pd that can exist under physiological conditions or in living cells, which could have adverse effects on both our health and environment. Thus, it is of great significance to monitor the changes of Pd²⁺. Hence, a novel near-infrared fluorescent probe M-PD has been developed for selective detection of Pd²⁺ based on naphthofluorescein in this work. The result demonstrated that M-PD exhibited favorable properties for sensing Pd²⁺ such as excellent water solubility, high selectivity and sensitivity. And the limit of detection was estimated as 10.8 nM, much lower than the threshold in drugs (5-10 ppm) specified by European Directorate for the Quality Control of Medicines. More importantly, detection and recovery experiments of Pd²⁺ in aspirin aqoeous solution and soil are satisfactory. In addition, M-PD has also been successfully used for near-infrared fluorescence imaging of Pd²⁺ in living cells, indicating that the probe has better feasibility and application potential in the determination of Pd²⁺.