Tryptophan (TRP) in the human body is generally metabolized by two different pathways, to serotonin or via kynurenine (KYN), where majority consumed through latter. Studies relate that imbalance between these pathways associated with types of diseases. This work aims investigate for first time redox properties KYN aqueous electrolytes on glassy carbon electrode (GCE), using electrochemical techniques, cyclic voltammetry (CV), differential pulse (DPV), square wave (SWV), and impedance...

Abstract This study investigates redox properties of fluorescein (FLSC), a fluorescent tracer with many applications in several areas, markedly biochemical research and health care diagnosis, on glassy carbon electrode (GCE) at wide interval pH by using voltammetric techniques. Three peaks were observed different potentials. The investigation revealed that FLSC is irreversibly electroxidized under diffusion‐controled pH–dependent process. oxidation process acid physiological media occurs two...

Abstract Rituximab (RTX) is a human/murine chimeric monoclonal antibody (mAb) that specifically targets the transmembrane protein CD20 of B‐cells. The oxidation mechanism native and denatured RTX was investigated on glassy carbon electrode. denaturing agent sodium dodecyl sulfate redutancts tris(2‐carboxyethyl)phosphine dithiothreitol were used. Significant differences observed for due to morphological changes unfolding structure. Native presented only one peak tyrosine tryptophan residues,...

Abstract The electrochemical behavior of antioxidants daidzein (DZ) and 7‐hydroxy‐4‐chromone (7‐OH‐4‐CHM) was investigated. oxidation DZ is irreversible, pH‐dependent, occurs in two steps, the first 4′‐OH on B‐ring second 7‐OH A‐ring. 7‐OH‐4‐CHM A‐ring, pH‐dependent proceeds a single step. diffusion coefficient calculated pH 7.0 phosphate buffer to be D =8.1×10 −5 cm 2 s −1 . detection limits as LOD =0.08 µM =0.13 µM.

No displacement of researchers, no transport, less toxic contact, fast, and low-cost analytical method.

Abstract BACKGROUND This work proposes the use of a simple, inexpensive method for hydrothermal synthesis fluorescent carbon dot nanoparticles (CDs) from rice starch aimed at determination Hg 2+ in water. The proposed involved using paper‐based analytical device coupled to 3D plate, with UV‐LED chamber and smartphone acquisition analysis fluorescence digital images CDs. RESULTS size dots ranged 0.5 3 nm, an average particle ~1 nm. functionalization methimazole allowed high selective...

Abstract The anodic oxidation of the hydroxyanthraquinones carminic acid (CA) and chrysazin (CR) was investigated. CA proceeds in a pH‐dependent cascade mechanism, concerning hydroquinone, catechol 3‐OH groups anthraquinone moiety. hydroquinone following electron‐donating occurs first at low positive potentials, group is oxidized irreversibly higher potential. CR successive steps. Oxidation tautomer CR‐ring first, symmetrical 1‐OH 8‐OH are same

Abstract A multilayer dsDNA‐electrochemical biosensor for the in situ electrochemical evaluation of anticancer antibody rituximab (RTX) interaction with double‐stranded DNA (dsDNA), differential pulse voltammetry was used. The decrease dsDNA oxidation peaks incubation time observed and confirmed that RTX binds causing condensation, no evidence base oxidative damage detected electrochemically. Nondenaturing agarose gel‐electrophoresis RTX‐dsDNA samples occurrence condensation structure.

Abstract Raltitrexede (RTX) is a folate analogue that belongs to the antimetabolites family and has antineoplastic activity correlated inhibition of thymidylate synthase (TS) enzyme. This study addresses electrochemical characterization RTX at glassy carbon electrode, on wide interval pH, using voltammetric techniques. The interaction between double helix DNA (dsDNA) in physiological medium also addressed, DNA‐electrochemical biosensor. A mechanism for oxidation proposed. irreversibly...

Abstract The electrochemical behavior of ethidium bromide (EtBr) on a glassy carbon electrode (GCE) was studied by cyclic, square wave and differential pulse voltammetry over wide pH interval. results revealed that the oxidation mechanism EtBr is an irreversible adsorption‐controlled process occurs in two consecutives steps. first step pH‐dependent at amino group C8 position with formation ortho ‐ para ‐quinone derivatives, while second pH‐independent C3 position. A method for quantitative...

Abstract This work presents a study of the electrochemical oxidation 7‐methylguanine (7‐mGua) in aqueous solution at glassy carbon electrode by cyclic voltammetry, differential pulse square wave voltammetry and impedance spectrometry. The anodic behaviour 7‐mGua was compared with electro‐oxidation guanine 7‐methylguanosine. results demonstrated that methyl ribose groups are not electroactive but strongly influence mechanism these species. occurred single pH‐dependent step, withdrawal two...