ascorbic-acid and cobalt-oxide

The surface tailored metal oxide nanostructures for the development of non-enzymatic sensors are highly demanded, but it is a big task due to the wide range of complexities during the growth process. The presented study focused on the surface modification of the heterogeneous morphology of cobalt oxide (Co

Topics: Ascorbic Acid; Citric Acid; Electrochemical Techniques; Nanostructures; Oxides; Sodium Citrate

Following accidental inhalation of radioactive cobalt particles, the poorly soluble and highly radioactive Co

Topics: Ascorbic Acid; Cobalt; Edetic Acid; Humans; Lung; Oxides; Pentetic Acid

The research reports a novel green method to use citrus fruits for the management of spent NMC based lithium ion batteries (LIBs). Citrus fruit juice (CJ) can provide an excellent chemical combination to remove the binder and support the leaching with efficiency in between 94% to 100%. CJ have many advantages in LIBs recycling as an economic and green method due to rich in many organic acids like citric and malic acid as complexing agents with ascorbic acid and citrus flavonoids, for the reduction of many heavy metals. Application of CJ can avoid the use of N-Methylpyrrolidine, γ-Butyrolactone, dimethylformamide, and dimethyl sulfoxide like toxic solvents commonly used for peeling off Al/Cu. Furthermore, counterions (like Na

Topics: Ascorbic Acid; Citrus; Cobalt; Electric Power Supplies; Flavonoids; Green Chemistry Technology; Lithium; Manganese; Metals; Nickel; Oxides; Recycling; Spectroscopy, Fourier Transform Infrared; X-Ray Diffraction

The Co3O4/CuO composite nanopowder (NP) was synthesized by a mechanochemical method and characterized by using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The synthesized Co3O4/CuO NP was used as a modified carbon paste electrode (MCPE) and further the bare carbon paste and Co3O4/CuO NP modified carbon paste was heated at different temperatures (100, 150, 200 and 250 °C) for 10 min. The Co3O4/CuO NP MCPE was used to study the consequences of scan rate and dopamine concentration. Furthermore the preheated modified electrodes were used to study the electrochemical response to dopamine (DA), ascorbic acid (AA) and uric acid (UA).

Topics: Ascorbic Acid; Carbon; Cobalt; Copper; Dopamine; Electrochemical Techniques; Electrodes; Hot Temperature; Nanostructures; Oxides; Uric Acid

Nanostructured enzyme mimics are of great interest as promising alternatives to artificial enzymes for biomedical and catalytic applications. Studying the chemical interactions between antioxidants and nano-enzymes may result in a better understanding of the antioxidant capability of antioxidants and may help improve the function of artificial enzymes to better mimic natural enzymes. In this study, using Co3O4 nanoparticles (NPs) as peroxidase mimics to catalyze the oxidation of chromophoric substrates by H2O2, we developed a platform that acts as a biosensor for hydrogen peroxide and glucose and that can study the inhibitory effects of natural antioxidants on peroxidase mimics. This method can be applied specifically to glucose detection in real samples. Three natural antioxidants, gallic acid (GA), tannic acid (TA), and ascorbic acid (AA), were compared for their antioxidant capabilities. We found that these three antioxidants efficiently inhibit peroxidase-like activity with concentration dependence. The antioxidants showed different efficiencies, in the following order: tannic acid > gallic acid > ascorbic acid. They also showed distinct modes of inhibition based on different interaction mechanisms. This study serves as a proof-of-concept that nano-enzyme mimics can be used to evaluate antioxidant capabilities and to screen enzyme inhibitors.

Topics: Antioxidants; Ascorbic Acid; Biosensing Techniques; Catalysis; Cobalt; Colorimetry; Enzyme Inhibitors; Gallic Acid; Glucose; Humans; Hydrogen Peroxide; Metal Nanoparticles; Microscopy, Electron, Transmission; Nanotechnology; Oxidation-Reduction; Oxides; Oxygen; Peroxidase; Tannins; X-Ray Diffraction

An electrochemical sensor for selective detection of ascorbic acid (AA) in the presence of dopamine (DA) and uric acid (UA) was fabricated by modifying the glassy carbon electrode (GCE) with carbon-supported NiCoO2 (NiCoO2/C) nanoparticles. The electrochemical impedance spectroscopic (EIS) studies reveal the little charge transfer resistance for the modified electrode. The electrocatalytic activity of the modified electrode for the oxidation of AA was investigated. The current sensitivity of AA was enhanced to about five times upon modification. The voltammetric response of AA was well resolved from the responses of DA and UA, and the oxidation potential of AA was negatively shifted to -0.20 V. The biosensor tolerated a wide linear concentration range for AA, from 1.0 × 10(-5)M to 2.63 × 10(-3)M (R(2)=0.9929), with a detection limit of 0.5 μM (S/N = 3). Our results demonstrate that the NiCoO2/C nanomaterials has excellent AA sensing capability, including a fast response time, high reproducibility and stability, with great promise in the quantification of AA in real samples. That makes it a unique electrochemical sensor for the detection of AA which is free from the interference of DA, UA and other interferents.

Topics: Ascorbic Acid; Biosensing Techniques; Carbon; Cobalt; Conductometry; Equipment Design; Equipment Failure Analysis; Metal Nanoparticles; Microelectrodes; Nickel; Oxides; Particle Size; Reproducibility of Results; Sensitivity and Specificity

In this work, we have developed a simple and reliable cobalt oxide (Co₃O₄) based amperometric sensor for the determination of NADH. A sheet shape Co₃O₄ nanooxide was synthesized by the CTAB assisted hydrothermal technique and was characterized by SEM and XPS. Owing to the redox property of Co₃O₄, the operating potential of NADH can be significantly reduced from 0.7 down to 0.1 V. Compared to a commercial Co₃O₄ nanoparticle modified electrode, this nanosheet form cobalt oxide possesses a rapid background subsiding characteristic and a low residual current. This scheme was conducted on a flow injection system with a constant operating potential of 0.1 V (vs. Ag/AgCl, 3 M) in a 0.2 M phosphate buffer at pH 6.0. A suitable linear range from 10 to 100 μM (R=0.999) with a detection limit of 4.25 μM (S/N=3) was obtained. The RSD for 20 successive measurements of 75 μM NADH is only 1.4%, which indicates a high stability and no contamination during NADH oxidation. This scheme did not suffer from conventional antioxidants, including dopamine, uric acid, epinephrine, serotonin, histamine, and 4-acetaminophen, except ascorbic acid. Thus, an ascorbate oxidase was introduced to remove the ascorbic acid before the sample was injected into the flow injection analysis system. After this simple pretreatment, the influence of ascorbic acid was eliminated, successfully.

Topics: Ascorbic Acid; Biosensing Techniques; Cobalt; Dopamine; Electrodes; Epinephrine; Histamine; Metal Nanoparticles; NAD; Oxidation-Reduction; Oxides; Serotonin; Uric Acid