Amperometry

Résumé

Amperometry in chemistry is detection of ions in a solution based on electric current or changes in electric current. Amperometry is used in electrophysiology to study vesicle release events using a carbon fiber electrode. Unlike patch clamp techniques, the electrode used for amperometry is not inserted into or attached to the cell, but brought in close proximity of the cell. The measurements from the electrode originate from an oxidizing reaction of a vesicle cargo released into the medium. Another technique used to measure vesicle release is capacitive measurements. History Electrochemical or amperometric detection as it was first used in ion chromatography was single-potential or DC amperometry, useful for certain electrochemically active ions such as cyanide, sulfite, and iodide. The development of pulsed amperometric detection (PAD) for analytes that fouled electrode surfaces when detected eventually helped create a new category of ion chromatography for the determina

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https://en.wikipedia.org/wiki/Amperometry

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An original selective and quantitative detection method for direct access to reactive oxygen species (ROS) generated in near-neutral aqueous solutions during transient electrochemical experiments is described herein. Several chemiluminescent probes, which were selected for their high selectivity toward ROS were used and the selective electrogenerated chemiluminescence (SECL) method was validated on several electrocatalytic materials known to exhibit different behaviors toward the oxygen reduction reaction (ORR); the examined electrodes consisted of platinum, Au(1 1 1), glassy carbon and boron-doped diamond (BDD). We first selected appropriate molecular probes that are suitable for use under electrochemical polarization conditions and that are chemiluminescent in the chosen aqueous solutions. The roles of the concentration, solubility and possible activation of the molecular probes were identified. Then, the information obtained by the simultaneous recording of the amperometric signal was correlated with the chemiluminescence intensity, which was measured with a highly sensitive photomultiplier tube (PMT). The experimental results were interpreted by constructing a potential vs. pH diagram for the oxygenated species. The complementary nature of the information about the mechanistic path of the ongoing mechanism of ORR on the different electrode materials allowed us to propose a unified scheme. A coupled proton electron transfer (CPET) mechanism can be invoked to explain the major differences observed from the identified reactive intermediates in relation to the electrocatalytic activity of the electrode materials. (c) 2013 Elsevier Ltd. All rights reserved.

Pergamon-Elsevier Science Ltd2013

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Decorated graphene oxide flakes with integrated complex of 8-hydroxyquinoline/NiO toward accurate detection of glucose at physiological conditions

Ulf Anders Hagfeldt, Seyyed Alireza Hashemi

The dramatic increase in the number of diabetic people raised the requirement for developing practical diagnostic setups capable of rapid and precise detection of glucose molecules at physiological conditions through non-enzymatic approaches. To address this requirement, we have developed a highly stable and sensitive nonenzymatic glucose biosensor consisted of decorated graphene oxide (GO) with an integrated platform of nickel oxide, 8-hydroxyquinoline (8H) and N-hydroxysuccinimide (NHS) (GO-NiO-8H-NHS) that enables the detection of glucose at neutral pH values. The optimum platform showed a perfect detection limit (DL) and sensitivity of 41 nM and 712.5 mu A.mM-1.cm-2, respectively, via amperometric technique, while these values for voltammetric approaches were measured to be 63 nM and 4911.4 mu A.mM-1.cm-2, respectively, at physiological conditions. Correspondingly, the developed platform showed superior sensitivity and accuracy toward detecting glucose within actual blood plasma samples and kept 94% of its initial performance after 30 days. Obtained outcomes revealed the fantastic DL and sensitivity of the developed non-enzymatic biosensors toward detecting glucose in actual biological samples at physiological conditions without using hazardous alkaline solutions.

ELSEVIER SCIENCE SA2021

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Amperometric Detection of Alkali Metal Ions on Micro Fabricated Composite Polymer Membranes

Hubert Girault

1998

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