Antioxidant Determination with the Use of Carbon-Based Electrodes

Abstract

Antioxidants are compounds that prevent or delay the oxidation process, acting at a much smaller concentration, in comparison to that of the preserved substrate. Primary antioxidants act as scavenging or chain breaking antioxidants, delaying initiation or interrupting propagation step. Secondary antioxidants quench singlet oxygen, decompose peroxides in non-radical species, chelate prooxidative metal ions, inhibit oxidative enzymes. Based on antioxidants’ reactivity, four lines of defense have been described: Preventative antioxidants, radical scavengers, repair antioxidants, and antioxidants relying on adaptation mechanisms. Carbon-based electrodes are largely employed in electroanalysis given their special features, that encompass large surface area, high electroconductivity, chemical stability, nanostructuring possibilities, facility of manufacturing at low cost, and easiness of surface modification. Largely employed methods encompass voltammetry, amperometry, biamperometry and potentiometry. Determination of key endogenous and exogenous individual antioxidants, as well as of antioxidant activity and its main contributors relied on unmodified or modified carbon electrodes, whose analytical parameters are detailed. Recent advances based on modifications with carbon-nanotubes or the use of hybrid nanocomposite materials are described. Large effective surface area, increased mass transport, electrocatalytical effects, improved sensitivity, and low detection limits in the nanomolar range were reported, with applications validated in complex media such as foodstuffs and biological samples.

Phytochemical Composition and Antioxidant Activity of Various Extracts of Fibre Hemp (Cannabis sativa L.) Cultivated in Lithuania

“…ROS are inevitably produced as a by-product of normal aerobic metabolism and could be injurious for cells when present in excess under stress conditions [ 85 ]. It was considered reasonable to evaluate the antioxidant properties of polyphenols and plant extracts by their capabilities to scavenge those ROS [ 86 ]. To assess the H 2 O 2 -scavenging activity of extracts of plants, the kinetic approach by monitoring the kinetics of hydrogen peroxide scavenging at Prussian Blue (PB)-modified electrodes [ 87 ] was chosen.…”

Low-Grade Thermal Energy Harvesting and Self-Powered Sensing Based on Thermogalvanic Hydrogels

“…There are few studies on new thermogalvanics for non-aqueous systems because mass transport is the main limiting factor rather than the charge transfer on the electrode [ 88 , 89 ]. Carbon-based electrodes are gaining increasing attention as a convenient and low-cost alternative to precious metal electrodes [ 90 , 91 , 92 , 93 ]. Nanostructured carbon materials, because of their high specific surface area, can increase the number of reaction sites, for example, nanotubes and graphene [ 94 , 95 , 96 , 97 ].…”

Antioxidant Capacity Assays. Chemical and Cellular-based Methods

“…A disadvantage of these methods is the difficulty of analysing macromolecules with antioxidant properties. https://doi.org/10.37358/RC.23.3.8569 A review of electrochemical sensors and biosensors used in assessing antioxidant activity [87], a review of electrochemical methods of antioxidant determination in plants and food extracts [100] and a review regarding antioxidant determination with the use of carbon-based electrodes [101] were published recently.…”