We demonstrate, for the first time, the use of plasmonic semiconductor nanocrystals for the analysis of heavy metal ions in water. This highly sensitive localized surface plasmon resonance (LSPR)-based platform is built on glutathione (GSH) capped Cu2-xS nanocrystals, which exhibit LSPR at near infrared (NIR) wavelengths. Aggregation of GSH-capped Cu2-xS occurs specifically in the presence of lead ions, Pb2+, producing a shift in the LSPR absorbance peak. Under optimal assay conditions, the detection limit was as low as 0.25 μM (52.5 ppb) of Pb2+. This provides a new plasmonic semiconductor nanocrystal-based assay for the detection of environmentally hazardous materials. The assay employs non-toxic and earth-abundant elements and could potentially be produced at much lower cost than similar gold nanoparticle-based assays.
- Aggregation-induced detection
- Copper sulfide
- Heavy metal ion
- Semiconductor nanocrystals
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