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.

Identification patterns of Trichoderma strains using morphological characteristics, phylogenetic analyses and lignocellulolytic activities.

Trichoderma is a genus of soil-borne fungus with an abundance of reports of its economic importance in the agriculture industry. Thus, the correct identification of Trichoderma species is necessary for its commercial purposes. Globally, Trichoderma species are routinely identified from micro-morphological descriptions which can be tedious and prone to errors.