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

This research delves into the holistic hydrothermal synthesis of VS QDs and their subsequent utilization as a fluorescent probe for the subtle detection of ferric ions (Fe) 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 VS QDs feature a surface densely populated with functional groups. While the VS QDs showcase interactions with multifarious metal ions in aqueous media, they set forth a pronounced and selective fluorescent quenching response toward Fe 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 ∼ 0.8 × 10 M) and remarkable selectivity for Fe ions, harnessing the intrinsic photoluminescent characteristics of VS QDs. In addition, a sophisticated portable smartphone platform, integrated with a radiometric fluorescence probe specifically tailored for in-situ detection of Fe 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 Fe in complex real-world samples.