Delphinidin immobilized on silver nanoparticles for the simultaneous determination of ascorbic acid, noradrenalin, uric acid, and tryptophan

AbstractIn the present study, the fabrication of a new modified electrode for electrocatalytic oxidation of noradrenalin, based on the delphinidin immobilized on silver nanoparticles modified glassy carbon electrode. Cyclic voltammetry was used to investigate the redox properties of this modified electrode. The surface charge transfer rate constant (ks) and the charge transfer coefficient (α) for the electron transfer between the glassy carbon electrode and the immobilized delphinidin were calculated. The differential pulse voltammetry exhibited two linear dynamic ranges and a detection limit of 0.40μM for noradrenalin determination. Moreover, the present electrode could separate the oxidation peak potentials of ascorbic acid, noradrenalin, uric acid, and tryptophan in a mixture. The usefulness of this nanosensor was also investigated for the determination of ascorbic acid, noradrenalin, and uric acid in pharmaceutical and biological fluid samples with satisfactory results

Glutathione detection at carbon paste electrode modified with ethyl 2-(4-ferrocenyl-[1,2,3]triazol-1-yl)acetate, ZnFe2O4nano-particles and ionic liquid

The purpose of the present study was to introduce a newly designed approach for deter-mination of glutathione using modified carbon paste electrode with ZnFe2O4nanoparticles, ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and ethyl-2-(4-ferrocenyl--[1,2,3]triazol-1-yl)acetate (EFTA/ZFO/IL/CPE). According to the results from the electro-chemical experiments, oxidation current of glutathione on the modified electrode surface was incremented and its oxidation potential was decreased compared to bare CPE. A linear response was observed for the electrode at different glutathioneconcentrations (0.2 to 300.0 μM)

A sensitive Cu(salophen) modified screen-printed electrode for simultaneous determination of dopamine and uric acid

This research applied a nanostructured electrochemical sensor with a screen-printed electrode (SPE) for examining the dopamine (DA) electrocatalytic oxidation when uric acid (UA) was present. Cu(salophen) nanostructured modified SPE (Cu(salophen)/SPE)was employed to investigate the electrochemical behavior of DA. At optimal pH (pH7.0), oxidation of DA at the modified electrode takes place at a potential around 100 mV less positive than at the unmodified SPE. Chronoamperometry was used to determine the diffusion coefficient of DA (D=1.96×10-5cm2s-1). Differential pulse voltammetry (DPV) showed linear response in the range between 0.2-450.0 μM for DA. The limit of detection (LOD) of DA was computed to be 0.05 μM. Moreover, Cu(salophen)/SPE was employed for determining DA in the presence of UA using DPV. The DPV results showed that at the modified electrode, two well-separated oxidation peaks of DA and UA could be obtained at potentials of 180 and 325 mV, respectively. This separation forms the basis for the co-detection of these two materials on the surface of Cu(salophen)/SPE. This sensor was then employed to determine DA and UA in real specimens

Electro-Organic Synthesis: An Efficient Method for the Preparation of Nanosized Particles of Phthalazine Derivatives via One-Pot Multicomponent Reactions

Aza heterocyclic compounds are major interest for organic chemists because of their mainly pharmacological activities and clinical applications such as antianxiety, antitumor, anticonvulsant, cardiotonic and vasorelaxant. This contribution describes an electrochemical approach for the preparation of nanosized particles of phthalazine in high yields and very short reaction time. The method is based on theone-pot multicomponent reaction (MCRs) of phthalhydrazide, malononitrile and aldehydes in propanol employing undivided cell in the presence of NaBr as an electrolyte. The product was characterized, after purification, using IR, 1H NMR, 13C NMR, MS and SEM. This procedure provides a method by which nanoparticles are synthesized directly from phthalhydrazide, malononitrile and aldehydes insides of a routine protocol for the synthesis of nano particles of organic compounds in which the synthesized organic compound is transformed into nanosized particles using modern high technology, for example ultrahighpressure rapid expansion of supercritical solution, and supercritical antisolvent with enhanced mass transfer. Size reduction is a fundamental unit operation having important applications in pharmacy. It helps to improve solubility and bioavailability, reduce toxicity, enhance release, and provide better formulation opportunities for drugs

Electro-Organic Synthesis of Nanosized Particles of 2-Amino-pyranes

We have developed a convenient and efficient method for the electrosynthesis of nanosized particles of 2-amino-pyrane derivatives through the reaction of aromatic aldehyde or isatin against malononitrile and 1,3-dicarbonyl compound inside an undivided cell where sodium bromide was present as electrolyte in propanol medium. This procedure resulted in efficient and selective formation of the products