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Electrochemical Transducers for Biosensors
Published in Sibel A. Ozkan, Bengi Uslu, Mustafa Kemal Sezgintürk, Biosensors, 2023
Ali A. Ensafi, Parisa Nasr-Esfahani
Commonly, the basis of amperometry is the continuous measurement of a current at a constant applied potential. The electrochemically active species cause the signal in the solution. It is proportional to the concentration of the species that oxidizes or reduces on the surface of the working electrode. Thus, the working electrode can act as an anode or cathode depending on the value of applied potential and the nature of the electroactive species. Amperometry is widely used in bioelectrochemical measurements because of its simplicity, wide dynamic range, and low detection limit (4). Actually, in amperometric detection, applying a constant potential minimizes the charging current, decreasing the background signal, which improves the detection limit. Furthermore, amperometric biosensors increase the sensor’s selectivity for a particular analyte because the oxidation or reduction of the analyte occurs at a specific potential, which is one of its characteristics (12).
Automatic Laboratory Analyzers
Published in Ernő Pungor, A Practical Guide to Instrumental Analysis, 2020
The method for glucose determination is based on amperometric detection by an enzyme electrode. The enzyme electrode is basically a platinum disk covered with a reaction layer containing glucose oxidase enzyme. A potential difference of 0.7 V is applied between the enzyme electrode and an Ag/AgCl reference electrode. In a background electrolyte in the absence of glucose a small current, the residual current flows. In the presence of glucose the following reaction takes place in the reaction layer: β-D-glucose +O2→glucose oxidasegluconic acid +H2O2
Sensors with 1-Dimensional Metal Oxide
Published in Zainovia Lockman, 1-Dimensional Metal Oxide Nanostructures, 2018
Khairunisak Abdul Razak, Nur Syafinaz Ridhuan, Noorhashimah Mohamad Nor, Haslinda Abdul Hamid, Zainovia Lockman
A few electrochemical sensors are assigned to three main types: potentiometric, amperometric, and conductometric. Potentiometric sensors measure the accumulated charge potential at the working electrode in an electrochemical cell as compared with the reference electrode when zero or no substantial current flows between them. Alternatively, it gives information on the ion motion in the reaction process. Amperometric sensors measure the resultant current caused by the oxidation or reduction of an electro-active species from the reaction process by utilizing applied potential between a reference and a working electrode. Typically, the current which is obtained at a constant potential is called amperometry while the current measured in various potentials is called voltammetry. Conductometric sensors measure the ability of an analyte or electrolyte solution to conduct electrical current between electrodes and reference electrode whose conductivity is affected by the presence of analyte. There are such practical reasons that make conductometric sensor attractive, such as inexpensive and easy as no reference electrodes are required (Stradiotto et al. 2003). The flow process of the reaction of analyte is shown in Figure 8.3.
Progress and challenges in electrochemical sensing of volatile organic compounds using metal-organic frameworks
Published in Critical Reviews in Environmental Science and Technology, 2019
Pawan Kumar, Ki-Hyun Kim, Parveen Kumar Mehta, Liya Ge, Grzegorz Lisak
Amperometric sensors are electrochemical sensors that measure current resulting from the oxidation or reduction of an electroactive species in a sample solution (Stradiotto et al., 2003; Stetter & Li, 2008). Typically, the current is measured at a constant potential (amperometry). When current is determined during controlled variations of the potential, it is generally referred to as voltammetry. As voltammetry also measures the current, it is considered to be a type of amperometric technique. As such, information is obtained from the current-concentration relationship with amperometric sensors.