A sensitive and rapid determination of zinc ion (Zn) using electrochemical sensor based on f-MWCNTs/CS/PB/AuE in drinking water.

An electrochemical method for detecting the presence of zinc (Zn) ions in drinking water was developed using functionalized multi-walled carbon nanotubes (f-MWCNTs) and chitosan (CS). Numerous cylinder-shaped graphene molecules make up f-MWCNTs, which have a high mechanical and electrical conductivity. CS benefits from nanomaterials include biocompatibility, biodegradability, and low toxicity, which are excellent in capacity absorption of metal ions.

Visual and Optical Absorbance Detection of Melamine in Milk by Melamine-Induced Aggregation of Gold Nanoparticles.

The present study reported a facile method for the determination of melamine in milk powder products based on the aggregation of reactant-free 5 nm gold nanoparticles (AuNPs). The strong electrostatic attraction between the positively charged exocyclic amine groups present in the melamine molecule and the negatively charged ions bound to the AuNPs induced aggregation of the AuNPs, resulting in visible color changes that could be seen with the naked eye and monitored by ultraviolet-visible (UV-Vis) absorbance spectra. The method shows high sensitivity with detection limits of 1 × 10 M for visual detection and 1 × 10 M for UV-Vis analysis, which is far below the safety limit of melamine ingestion in infant formula (1 ppm = 7.