A new palladium complex as a dual fluorometric and colorimetric probe for rapid determination of sulfide anion

Abstract A new BODIPY based Pd (II) complex, Pd-BDPA has been developed as a dual fluorometric and colorimetric probe for the detection of sulfide anion. The sensing ability is based on the interaction affinity of the Pd (II) towards the sulfide anion which is highly selective and immediate with a detection limit of 240 nM. The interaction between Pd (II) and sulfide is not only highly selective over the other common anions but also not interfered by their coexisting. This selective interaction between them leads to the regeneration of free ligand resulting in the dramatic changes in both fluorescence and absorption spectra. The fluorescent changes lead to quenching the emission spectra which is linear with the concentration of sulfide in the range of 1-10 μM. In addition to fluorescence quenching, the interaction also resulted in the significant color switching from purple to blue which was easily distinguished by the naked eye. Another important advantage is that the Pd-BDPA coated paper-based strips show the sulfide selectivity and sensitivity by the color changes as is in the solution form, revealing its practical utility more conveniently. In addition, the Pd-BDPA probe can also successfully be utilized for the determination of sulfide in real water samples with satisfactory recovery results indicating its feasibility for environmental samples.