Luminescent probes/conjugates derived from quantum dots, nanoparticles, and nanoclusters for cyanide (CN⁻) detection

Advancing the development of the luminescent nanoprobes and conjugates toward the toxic analyte quantification plays a crucial role in environmental remedy. Cyanide ions (CN⁻) play vital role in many industries, such as electroplating, mining, textiles, metallurgy, etc. The highly toxic CN⁻ may be discharged into the environment. The presence of CN⁻ in aquatic environment at micromolar level could lead to fatal issue in humans and living beings, which requires scrutiny to maintain the ecosystem. Thus, diverse probes, such as organic fluorophores, noble metal nanoparticles/clusters (NPs/NCs), carbon/graphene quantum dots (CQDs/GQDs), cadmium telluride/selenide quantum dots (CdTe QDs/CdSe QDs), cadmium/zinc/silver sulfide quantum dots (CdS QDs/ZnS QDs/ Ag₂S QDs), etc, were proposed toward the quantification of CN⁻ ions with real-time applications. Among them, the luminescent probes/conjugates derived from QDs, NPs, and NCs are unique and display astonishing selectivity and sensitivity to CN⁻. The observed luminescent responses can be attributed to agglomeration, inner filter effect (IFE), fluorescence resonance energy transfer (FRET), chemiluminescence resonance energy transfer (CRET), etc Till now there is no review article reporting the applications of the luminescent probes/conjugates derived from QDs, NPs, and NCs for CN⁻ quantification. In this review, the employment of these probes/conjugates for detecting CN⁻ is illustrated with detailed underlying mechanisms and real-time applications. Furthermore, the design requirements, advantages, limitations, and directions of the luminescent probes/conjugates are delivered for future studies.