A smartphone-enabled colorimetric sensor based on VS₂ quantum dots for Rapid and on-site detection of ferric ions

This research delves into the holistic hydrothermal synthesis of VS₂ QDs and their subsequent utilization as a fluorescent probe for the subtle detection of ferric ions (Fe³⁺) in practical sample matrices. The detection paradigms harness a colorimetric sensing mechanism, amplified by smartphone-enabled analytical integration for improved precision and real-time monitoring. A comprehensive suite of analytical characterization techniques has been employed, revealing that the as-synthesized VS₂ QDs feature a surface densely populated with functional groups. While the VS₂ QDs showcase interactions with multifarious metal ions in aqueous media, they set forth a pronounced and selective fluorescent quenching response toward Fe³⁺ ions, markedly surpassing their interactions with other metal ions. The developed sensing probe exhibits a linear detection range spanning from 0 - 90 μM, with a LOD as low as 2.25 μM, also exhibits exceptional sensitivity (K_D ∼ 0.8 × 10⁴ M^-1) and remarkable selectivity for Fe³⁺ ions, harnessing the intrinsic photoluminescent characteristics of VS₂ QDs. In addition, a sophisticated portable smartphone platform, integrated with a radiometric fluorescence probe specifically tailored for in-situ detection of Fe³⁺ at the point of care, exhibits a LOD of approximately 5.05 μM, a value that resides below the prescribed safety threshold. Thus, the proposed probe stands to function as an exceptionally potent sensing apparatus for the precise quantification of Fe³⁺ in complex real-world samples.