A colorimetric and fluorescent signaling probe for assaying Pd(2+) in practical samples

We developed an optical signaling probe to detect Pd(2+) ions in Pd-containing catalyst and drug candidate. The Pd(2+) signaling probe (Res-DT) was readily prepared by reacting the versatile fluorochrome resorufin with phenyl chlorodithioformate. In a phosphate-buffered saline solution (pH 7.4) containing sodium dodecyl sulfate (SDS) as a signal-boosting surfactant, Res-DT exhibited a pronounced colorimetric response with a chromogenic yellow to magenta shift, leading to a substantial increase in the fluorescence intensity. The Pd(2+) signaling performance of Res-DT was attributed to the Pd(2+)-promoted hydrolysis of the dithioate moiety. The probe displayed high selectivity toward Pd(2+) ions and remained unaffected by commonly encountered coexisting components. Moreover, the detection limit of Res-DT for Pd(2+) ions was 10 nM, and the signaling was achieved within 7 min. Furthermore, to demonstrate the real-world applicability of Res-DT, a Pd(2+) assay was performed in Pd-containing catalyst and drug candidate using an office scanner as an easily accessible measurement device. Our results highlight the prospects of Res-DT as a tool to detect Pd(2+) ions in various practical samples, with potential applications in catalysis, medicine, and environmental science.