title: Synthesis of water-soluble 2,2'-diphenyl-1-picrylhydrazyl nanoparticles: a new standard for electron paramagnetic resonance spectroscopy.
abstract: This communication reports a size-controlled synthesis of water-soluble 2,2'-diphenyl-1-picrylhydrazyl (DPPH) nanoparticles (NPs). These nanoparticles exhibit size-dependent absorption spectra and fast spin exchange-narrowed single-line EPR spectra. The linewidths of the EPR spectra of these water-soluble nanoparticles are approximately 1.5-1.8 G, which are equal or close to the narrowest line width (1.5 G) of the common DPPH standard in the form of water-insoluble microcrystals. In addition, these NPs are stable over a wide pH range of 3.0 to 10.0. These properties make these water-soluble DPPH NPs suitable for use as a new type of EPR standard, which is important for fundamental research and practical applications in fields such as the food industry and the life sciences. Furthermore, the DPPH NPs can potentially be used as a spin probe in biomedical studies.
authors: Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA.
authors: Ou
authors: O
authors: Chen
authors: Jiaqi
authors: J
authors: Zhuang
authors: Fabrizio
authors: F
authors: Guzzetta
authors: Jared
authors: J
authors: Lynch
authors: Alexander
authors: A
authors: Angerhofer
authors: Y Charles
authors: YC
authors: Cao