Electrochemical behavior of protein oxidation biomarkers meta-, ortho- and 3-chloro-tyrosine on carbon electrodes: A comparative study with para-tyrosine and phenylalanine. (July 2022)

• Record Type: Journal Article
• Authors: Nascimento, Maysa L.; Alves, Arthur S.; Nascimento, José A.M.; Santos, Vagner B.; Oliveira, Severino Carlos B.
• Is Part Of: Carbon trends. Number 8(2022)
• Publication Date: 2022-07
• Subjects: Meta-tyrosine -- Ortho-tyrosine -- 3-chloro-tyrosine -- Phenolic compounds -- Glassy carbon electrode -- Boron doped diamond electrode; Carbon -- Periodicals; Carbon composites -- Periodicals; Carbon; Carbon composites; Periodicals; 620.193
• DOI: 10.1016/j.cartre.2022.100182
• Languages: English
• ISSNs: 2667-0569

Abstract

Abstract: The anodic behavior of the isomers meta-, ortho- and para -tyrosine ( m-, o-, p -Tyr) and of phenylalanine in aqueous support electrolytes, with different pH values, on the glassy carbon electrode (GCE), were investigated and compared using cyclic and differential pulse voltammetry. The electrochemical behavior of 3 ‑ chloro -tyrosine (3-Cl-Tyr) in different aqueous media was also investigated on a GCE and boron-doped diamond electrode (BDDE). The results showed that all tyrosines undergo oxidation at the phenolic group, with the removal of one electron and one proton, forming one intermediate radical, Tyr ● . The reactivity of this radical in aqueous medium, however, is clearly conditioned by its position in the tyrosine structure. The m -Tyr ● reaction occurs with the formation of polymers and with water to form one quinone derivative. The o -Tyr ● radical reacts preferentially with water leading to formation of two electroactive quinone derivatives and p -Tyr ● preferentially follows the polymerization. The electrochemical results of the 3-Cl-Tyr electro-oxidation were very similar in relation to p -Tyr. There was little influence of the substituent -Cl, occurring in the phenolic group with predominantly polymer formation. On the other hand, unlike the other tyrosines, one irreversible and pH-dependent cathodic peak for 3-Cl-Tyr was detected, associated to the electro-reduction of the chloro group attached at C3. Using differential pulse voltammetry (DPV), experimental optimizations were also performed for quantification of 3-Cl-Tyr with low detection limit. These were carried out with a carbon working electrode (GCE or BDDE), support electrolyte composition and pH and considering possible interferents. Thus, electroanalytical methods for detection and quantification of 3-Cl-Tyr at carbon electrodes were also developed and proposed.