Detection and Quantification of Dysprosium in Plant Tissues

The growing demand for rare-earth elements (REEs), particularly dysprosium (Dy), underscores the need for sustainable extraction methods. Recovery of Dy, particularly from geographically distributed waste sources, is challenging. This gap positions phytomining, a technique using plants to accumulate metals, as a promising alternative. However, plant species differ in their ability to accumulate metals in high concentrations, necessitating efficient screening methods. In this study, we developed a high-throughput fluorescence-based assay to detect and quantify Dy uptake in plant tissues. The Dy detection method described in the present work exploits Dy's unique spectroscopic properties for sensitive and efficient analysis, enabling the detection of concentrations as low as 0.07 μM, with a detection limit of 0.2 μM in a plant matrix. By incorporating sodium tungstate (Na₂WO₄) as a fluorescence enhancer, we achieved robust emission intensities at 480 and 580 nm, facilitating Dy quantification in complex plant matrices. Additionally, the use of time-resolved fluorescence techniques reduces background autofluorescence from plant tissues, enhancing signal specificity. Validation of the fluorescence method with inductively coupled plasma mass spectrometry (ICP-MS) demonstrated a strong correlation in Dy levels. Greenhouse trials confirmed the method's utility for screening Dy accumulation in living plants and highlighted the potential for rapid stand-off detection. This fluorescence-based approach offers a scalable, efficient tool for identifying Dy-accumulating plants and advances phytomining as a sustainable strategy for REE recovery.