A "turn-off" photoluminescent sensor for HO detection based on a zinc oxide-graphene quantum dot (ZnO-GQD) nanocomposite and the role of amine in the development of GQD.

In this work, graphene quantum dots (GQD) were prepared through a hydrothermal process. The photoluminescence (PL) emission spectrum for GQD prepared with high NHOH concentration (sample D1-t) was attained at lower wavelength (406 nm), compared to GQD synthesized with low NHOH concentration (sample D2-t attained at 418 nm). From these results, a smaller particle size for D1-t was deduced; according to TEM images the GQD particles are around 5 nm.

Environmentally Friendly Methods for Flavonoid Extraction from Plant Material: Impact of Their Operating Conditions on Yield and Antioxidant Properties.

The flavonoids are compounds synthesized by plants, and they have properties such as antioxidant, anticancer, anti-inflammatory, and antibacterial, among others. One of the most important bioactive properties of flavonoids is their antioxidant effect. Synthetic antioxidants have side toxic effects whilst natural antioxidants, such as flavonoids from natural sources, have relatively low toxicity.