Tb3+-xylenol orange complex-based colorimetric and luminometric dual-readout sensing platform for dipicolinic acid and metal ions

A dual-readout sensing platform based on two signal transduction channels can integrate the unique advantages of each sensing pattern, compensate for the deficiency in the adaptive capacity, and enable a more convincing performance in analytical applications. Here, we introduce a responsive molecule dye, xylenol orange (XO), to combine with lanthanide terbium ions (Tb3+). The resultant Tb3+-XO complex exhibited tunable optical properties and was used as a novel colorimetric and luminometric dual-readout sensing platform for assaying the anthrax biomarker, dipicolinic acid (DPA). In the presence of Tb3+, the XO solution underwent a color change from yellow to magenta; however, upon adding DPA, the color changed back to yellow immediately, accompanied by the characteristic luminescence emission of Tb3+. Considering the strong affinity between DPA/XO and metal ions, the proposed sensing platform was further employed for the determination and differentiation of certain metal ions using linear discriminant analysis. This convenient dual-readout sensing platform offers several notable features and significantly promotes the application and development of lanthanide-based materials.