Recently, the paper A convenient colorimetric method for sensitive and specific detection of cyanide using Ag@Au core-shell nanoparticles by Li Yiran, an undergraduate from College of Chemical Engineering was published by Sensors and Actuators B: Chemical. Ag@Au core–shell NPs are synthesized and used as probes for cyanide sensing. Ag@Au core–shell NPs before and after cyanide treatment are characterized with UV–vis spectroscopy, transmission electron microscopy and electrospray ionization time-of-flight mass spectrometry.
In fact, the assay in the paper is very convenient without relying on complicated organic synthesis and sophisticated equipment, but allows a high sensitivity with a LOD of 0.16 μM, which is much lower than the maximum allowable concentration of cyanide (1.9 μM) in drinking water regulated by the WHO. More importantly, it exhibits excellent selectivity towards cyanide over other common anions and cations, which is due to the fact that Au is inert and stable. With the aid of PS 40 as a stabilizer, the PS 40-Au NPs were able to detect cyanide in sewage water samples with complex matrices. These striking properties make the proposed assay suitable for the rapid and reliable on-site monitoring of cyanide concentration in water samples, which is beneficial for immediate evaluation of unexpected risk and danger.
Learn More about the assay http://www.sciencedirect.com/science/article/pii/S0925400516300223