Interfacial covalent assembly of CdTe QDs on Eu3+-modified NH2-UiO-66 for Ratiometric fluorescence detection and adsorption of glyphosate

A covalently coupled CdTe/NH₂-UiO-66(Eu) ratiometric probe was developed. • Adsorption experiments and IGM analysis indicated rapid glyphosate uptake mediated by multiple interfacial interactions. • Glyphosate enhanced blue emission and weakened green emission for ratiometric readout. • Lifetime, XPS, and TD-DFT analyses provided mechanistic insights into the fluorescence response. Rapid detection and effective adsorptive capture of glyphosate from water are important for aquatic environmental monitoring and agricultural product safety. To address the susceptibility of single-emission fluorescence signals to external fluctuations and the limited glyphosate-capture capability of conventional fluorescent probes, a dual-emission platform integrating glyphosate adsorption with ratiometric fluorescence detection was constructed through the covalent interfacial assembly of Eu 3+ -modified NH 2 -UiO-66 and mercaptopropionic acid-modified CdTe QDs. Adsorption experiments and independent gradient model (IGM) analysis indicated that the composite exhibited rapid glyphosate uptake mediated by multiple interfacial interactions. In the presence of glyphosate, CdTe/NH 2 -UiO-66(Eu) exhibits enhanced blue emission at 434 nm and weakened green emission at 524 nm, producing a pronounced I 434 /I 524 ratiometric response. The fluorescence intensity ratio shows a linear dependence on glyphosate concentration over the range of 0.5–80 μM, with a limit of detection of 0.217 μM. Based on fluorescence lifetime results and XPS analysis, the ratiometric fluorescence response mechanism of the probe was elucidated. TD-DFT calculations further suggested that glyphosate modifies the excited-state charge distribution and charge-transfer characteristics associated with the MOF component. This work provides an interfacial assembly strategy for constructing MOF-based platforms that combine adsorptive glyphosate capture with ratiometric fluorescence sensing. Download: Download high-res image (182KB) Download: Download full-size image