Quantification of Catechins in Tea Using Cyclic Voltammetry

Abstract

Flavonoids have been studied extensively for their antioxidant properties. Specifically, the flavonoids in tea, such as catechin and epigallocatechin gallate, have been shown to have positive health effects. These compounds are also oxidizable, so the concentrations of these compounds in a given kind of tea can be determined using cyclic voltammetry. Green, black, oolong, and herbal teas were each diluted using pH 7.0 phosphate buffer, analyzed using cyclic voltammetry, and compared to the standards of epigallocatechin gallate, catechin hydrate, and catechol. The effect of brewing temperature on the concentration of catechins was also examined. Students learned about the common flavonoids in tea and the effect of brewing temperature on the concentration of catechins in solution.

Bioactive Phenolic Compounds from Lingonberry (Vaccinium vitis-idaea L.): Extraction, Chemical Characterization, Fractionation and Cellular Antioxidant Activity

“…The shape of the signal from cyclic and square wave voltammetry indicated the oxidation of similar chemical compounds in all extracts examined. More precisely, the shape of the signal from voltammograms implies the oxidation of compounds that include O-dihydrobenzene (catechol) in their structure to O-quinone and then reversed reduction in the catechol form [46]. The intensity of the signal could be an indicator of the antioxidant potential of the extracts.…”

Electrochemical sensing of dobutamine, paracetamol, amlodipine, and daclatasvir in serum based on thiourea SAMs over nano-gold particles–CNTs composite

“…The TU surface coverage is 1.29 × 10 −10 mol cm −2 . 77 The electrochemical oxidation signals of the studied compounds: DB, AM, and DAC are improved by using the TU-SAMs electrode. Two kinds of interactions are present for every compound, the first interaction is between Au nano and the sulfur in the TU molecule forming a strong covalent bond (Au nano –S), and the second is the formation of hydrogen bonds between TU-SAMs and DB, AM, and DAC compounds through the amino groups of TU molecules and the two OH-groups of DB, the NH-group of AM and the two NH-groups of DAC (molecular interaction) as indicated in Scheme 1.…”

Synthesis and Characterization of a Metal-Free Organic Dye-Sensitizer for Solar Cell: An Advanced Organic Chemistry Research-Based Laboratory

“…The HOMO and LUMO energies can be estimated from the cyclic voltammetry according to Koopman’s theorem where the first oxidation potential corresponds to the HOMO, and the reduction potential to the LUMO energies . In order to measure the first oxidation potential ( E ox ) corresponding to the HOMO of the synthesized dye, students collected the cyclic voltammograms in CH 2 CI 2 and performed an in-depth analysis of the electronic and redox properties of the organic dye-sensitizer. − The cyclic voltammogram of 4 in CH 2 CI 2 exhibits an irreversible reduction peak at −1.80 V vs NHE, and a quasi-reversible oxidation peak at 1.34 V and an irreversible oxidation peak at 1.84 V vs NHE (Figure ). − The HOMO and LUMO energy levels of 4 are presented in Figure by comparing them to the redox potential of the electrolyte, and to the conduction band of TiO 2 , respectively.…”