Trichloric acetic acid

GO was prepared using a modified Hummers method and purified as described previously.⁶⁸ RGO was produced by heating multilayer GO flakes at 250 C for 30 min in nitrogen flow. Few layer graphene (3–5 layers with nominal lateral dimension of 800 nm) was obtained commercially and characterized. Ascorbic acid, titanium (IV) oxide (TiO₂) nanopowders (<25 nm particle size, >99.5 % trace metal basis), iron (II) sulfate haptahydrate (FeSO₄·7H₂O), reduced GSH, D-mannitol, pC60, xanthine, xanthine oxidase from bovine milk grade IV,2,2′-azobis(2-amidinopropane) hydrochloride (AAPH), thiobarbituric acid (TBA), trichloricacetic acid (TCA), DPPH, 2-deoxy-D-ribose (deoxyribose), sodium dodecyl sulfate (SDS), ABTS, β-Nicotinamide adenine dinucleotide 23-phosphate reduced tetrasodium salt hydrate (NADH), phenazinemethosulfate (PMS), xanthine, xanthine oxidase from bovine milk, and NBT were purchased from Sigma Chemicals Co (St. Louis, MO). Hydrogen peroxide (H₂O₂), phosphate buffered saline (PBS) (pH 7.4), and EDTA were purchased from Fisher Scientific Inc. (Pittsburgh, PA). 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) were purchased from Dojindo Molecular Technologies, Inc. (Rockville, MD). ThioGlo-1 Fluorescent Thiol Reagent is purchased from EMD Millipore Chemical (Darmstadt, Germany), Nanopure water was used throughout.