Trace analysis of cadmium in the environment is of immense interest due to the associated health effects on humans.  Cadmium enter the body through inhalation, ingestion, and skin absorption.  Divalent Cadmium is found in trace quantities in toys, food and environmental samples. Motivated by this need we have synthesized glutathione modified gold nanoparticles for trace level cadmium detection in environmental samples. It is well-known that unmodified gold nanoparticles are susceptible to aggregation under high salt concentrations. However, glutathione, prevents the aggregation of gold nanoparticles and stabilizes unlike other ligands. Further, addition of cadmium to this solution results in the formation of a spherical shaped complex that can bind four glutathione molecules. Therefore, gold nanoparticles undergo aggregation in the presence of only cadmium resulting in an instant color change from wine red to deep blue. On the contrary, all the other competing metals ions form a linear complex resulting in no color change due to the lack of aggregation of the gold nanoparticles.<br/>Taking the advantage of the selective aggregation of glutathione modified gold nanoparticles with the presence of cadmium, a simple, label-free, highly selective, and ultrasensitive gold nanoparticle based dynamic light scattering (DLS) probe for Cadmium detection is developed. The aggregated gold nanoparticles change the dynamic light scattering (DLS) intensity tremendously. Our experimental results show that cadmium concentrations as low as 250nM can be detected colorimetrically and 10nM with our DLS assay rapidly and accurately with excellent discrimination against other ions in synthetic and environmental samples. The developed colorimetric probe is quite simple and rapid with excellent repeatability and has great potential for prototype scale up for field application.<br/>

Glutathione functionalized gold nanoparticle-dynamic light scattering tandem for rapid and selective detection of cadmium

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.