Influence of the synthesis surfactants on the electrochemical and physicochemical properties of copper zinc tin sulfide

Synthesis of nickel oxide/zirconia powders via a modified Pechini method

Surface plasma resonance (SPR) of nanoparticles has garnered significant attention among emerging analytical techniques due to their unique optical sensing properties. SPR peak shifts due to a change in local refractive index, and electrical interactions because of the binding of other molecules to the nanoparticle's surface. In this manuscript, we explore the SPR peak shifting due to redox reaction on the nanoparticle's surface and apply this SPR peak shifting for ascorbic acid (AA) sensing by cysteine‐coated silver nanoparticles (Cys–AgNPs). The SPR peak shifting of Cys–AgNPs was measured by UV–vis spectroscopy. We observed a red shift, depending on the concentration of AA when added to Cys–AgNPs. We observed a 46 nm SPR shift with 2 mM of AA in the case of Cys–AgNPs. However, no shift occurred with bare AgNPs. A redox reaction between L‐cysteine and AA occurring on the nanoparticle's surface is the reason for the shift. The sensing method is sensitive and selective to AA. The SPR peak shifting is not affected by the presence of biomolecules like fructose, glucose, alanine, glycine, and bovine serum albumin (BSA). This manuscript showed the simple synthesis of cysteine‐coated silver nanoparticles (Cys–AgNPs) and their characterization by UV–vis spectroscopy, dynamic light scattering (DLS), zeta potential, FT‐IR, XRD, SEM, TEM analysis, and SPR‐based AA sensing.

A sensor of a polyoxometalate and Au–Pd alloy for simultaneously detection of dopamine and ascorbic acid

Synthesis of colloidal silver nanoparticle clusters and their application in ascorbic acid detection by SERS

A novel colorimetric strategy for sensitive and rapid sensing of ascorbic acid using cobalt oxyhydroxide nanoflakes and 3,3′,5,5′-tetramethylbenzidine

Ascorbic acid is widely used in the food industry as a source of vitamin C or as antioxidant. However, it degrades quickly in beverages at acidic pH and can accelerate the degradation of anthocyanins, natural dyes used in beverages, leading to a loss of color. In this work, we investigated the possibility to replace ascorbic acid by ascorbic acid derivatives to prevent its degradation effect on anthocyanins from natural extracts (black carrot, grape juice, and purple sweet potato). For this, the thermal and photolytic stabilities under air and under N2 of ascorbic acid (as reference) and of some ascorbic acid derivatives (3-O-ethyl-l-ascorbic acid, 2-O-α-d-glucopyranosyl-l-ascorbic acid, l-ascorbic acid 2-phosphate sesquimagnesium salt hydrate, l-ascorbyl 2,6-dibutyrate, glyceryl ascorbate, (+)-5,6-O-isopropylidene-l-ascorbic acid), soluble in aqueous model beverages, were studied alone and in the presence of anthocyanins from the natural extracts in citrate buffer at pH 3. The stability was followed by UV-visible spectrometry. To extend the investigation, some properties of the ascorbic acid derivatives (pKa, oxidation potential, bond dissociation energy, ionization potential) were also determined. Moreover, the addition of chlorogenic acid was examined to further stabilize the mixture of anthocyanins with 2-O-α-d-glucopyranosyl-l-ascorbic acid, a promising ascorbic acid derivative.

Selective determination of 3,4-dihydroxyphenylacetic acid in the presence of ascorbic acid using 4-(dimethylamino)pyridine capped gold nanoparticles immobilized on gold electrode

Synthesis, antioxidant, DNA interaction, electrochemical, and spectroscopic properties of chromene-based Schiff bases: Experimental and theoretical approach

The facile and simple synthesis of poly(3,4ethylenedioxythiophene) anchored reduced graphene oxide nanocomposite for biochemical analysis

Electrochemical synthesis of carbon dots with a Stokes shift of 309 nm for sensing of Fe3+ and ascorbic acid

Fabrication and voltammetric study of lanthanum 2,6-dichlorophenolindophenol chemically modified screen printed electrodes.: Application for the determination of ascorbic acid

All-solid-state potentiometric sensors for ascorbic acid by using a screen-printed compatible solid contact

Myoglobin is an oxygen binding protein and its dysfunction has been associated with the pathology of several human disorders. This study was undertaken to investigation the role of hydrogen peroxide (H2O2) in the formation of met-myoglobin and the protective potential of four different reductants such as uric acid, folic acid, glutathione and ascorbic acid were also tested against met-myoglobin formation. Human myoglobin was treated with H2O2 in-vitro in order to prepare met-myoglobin. The generation of met-myoglobin was confirmed by UV-visible spectroscopy and its stability was analysed by the treatment of human myoglobin with H2O2 at varying pH or time. High performance liquid chromatography (HPLC) was used to determine the oxidatively modified heme products in met-myoglobin. Spectroscopic analysis was used to identify the protective potential of uric acid, folic acid, glutathione and ascorbic acid against the formation of met-myoglobin. The novel data of this study showed that H2O2 induced extensive damage of myoglobin but the treatment with uric acid, folic acid, glutathione or ascorbic acid provides protection of myoglobin against H2O2 induced oxidative damaged. The study apparently proved the protective potential of all these compounds against the toxicity produced by H2O2. This is the first study that shows uric acid, folic acid, glutathione and ascorbic acid provide protection against the generation of toxic met-myoglobin and might be used therapeutically to modify the blood conditions in order to prevent the progression of human disorders associated with myoglobin dysfunction.

Graphene, a single layer of sp2-hybridized carbon atoms in a hexagonal (two-dimensional honey-comb) lattice, has attracted strong scientific and technological interest due to its novel and excellent optical, chemical, electrical, mechanical and thermal properties. The solution-processable chemical reduction of Graphene oxide (GO is considered as the most favorable method regarding mass production of graphene. Generally, the reduction of GO is carried out by chemical approaches using different reductants such as hydrazine and sodium borohydride. These components are corrosive, combustible and highly toxic which may be dangerous for personnel health and the environment. Hence, these reducing agents are not promising choice for reducing of graphene oxide (GO). As a consequence, it is necessary for further development and optimization of eco-friendly, natural reducing agent for clean and effective reduction of GO. Ascorbic acid, an eco-friendly and natural reducing agents, having a mild reductive ability and nontoxic property. So, the aim of this research was to green synthesis of GO with ascorbic acid. For this purpose, the required amount of NaOH and ascorbic acid were added to GO solution (0.5 mg/ml) and were heated at 95 °C for 1 hour. According to the X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electrochemical results, GO were reduced with ascorbic acid like hydrazine with better electrochemical properties and ascorbic acid is an ideal substitute for hydrazine in the reduction of graphene oxide process.

Synthesis of Cu nanoparticles using chemical route offers a competitive alternative approach over the common biological and physical procedures. In this study, simple, economical, convenient and environmentally-friendly chemical reduction technique was used for the production of Cu nanoparticles from CuCl2.2H2O solution using L-ascorbic acid as reducing and capping agent. The effects of concentration of precursor salt and ascorbic acid, reaction time and reaction temperature on the synthesis of Cu nanoparticles were studied. The optical properties of the synthesized Cu nanoparticles were characterized by UV-Vis Spectroscopy while the crystallinity of synthesized Cu nanoparticles was verified with the help of X-ray diffraction analysis. The antimicrobial activity of Cu nanoparticles was determined by Agar disc diffusion method against some selected species of bacteria: two gram positive (Staphylococcus aureus, Streptococcus pyogenes) and two gram negative (Escherichia coli, Pseudomonas aeruginosa). The UV-Vis spectrum of solution of Cu nanoparticles showed a characteristic peak at 423 nm that confirms the preparation of Copper nanoparticles. Moreover, FT-IR spectroscopy was performed to detect the binding effect of ascorbic acid on Cu nanoparticles, and its result indicated that ascorbic acid could prevent oxidation and agglomeration. The findings revealed that Cu nanoparticles formed at a concentration of 3mM Cu- Cl2.2H2O solution and 4 mM ascorbic acid exhibited an excellent zone of growth inhibition for both gram-negative and gram-positive bacteria, 16.83+0.42 and 15.50+0.89mm, respectively.Keywords: - Green synthesis, Copper nanoparticles, Chemical reduction, Optical properties, Antibacterial activity