Novel studies about the electrochemical reduction of progesterone (P4) in acetonitrile at glassy carbon electrodes

Arévalo, Fernando Javier; Molina, Patricia G.; Zón, Marı́a Alicia; Fernández, Héctor

doi:10.1016/j.jelechem.2008.03.008

Cited by 16 publications

(14 citation statements)

References 34 publications

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“…The authors of the latter work also paid attention on the adsorption of progesterone on the working electrode surface, while evaluating thermodynamic parameters of the adsorption strength. The same group [136] has previously reported a comprehensive SWV study about the reduction of progesterone in acetonitrile at glassy carbon electrode. Electrochemical transformation of progesterone in a nonaqueous medium is accompanied by formation of stable radical anions.…”

Section: Analytical and Biochemical Applications Of Square-wave Voltamentioning

confidence: 99%

Square‐Wave Voltammetry: A Review on the Recent Progress

et al. 2013

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A review on the recent progress of square-wave voltammetry is presented, covering the period of the last five years. The review addresses the new theoretical development of the technique as well as its application for mechanistic purposes, electrode kinetic measurements, biochemical and analytical applications. Besides, a few novel methodological modifications are proposed that might expand the scope and application of the technique.

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Section: Analytical and Biochemical Applications Of Square-wave Voltamentioning

confidence: 99%

Square‐Wave Voltammetry: A Review on the Recent Progress

et al. 2013

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“…This behavior indicates that the product of the initial reduction step is consumed by a homogeneous chemical reaction coupled to the initial electron transfer reaction in agreement with results of cyclic voltammetry. 23,29 A tentative diffusion coefficient was calculated considering the convolution model for ECE (electron transfer) reaction mechanism. 29 where A is the electrode area, D CITH is the CITH diffusion coefficient and the other terms have their usual meaning, an average value of (6.77 ± 0.07) × 10 -6 cm 2 s -1 for D CITH was calculated in ACN plus 0.1 mol L -1 TBAP.…”

Section: Resultsmentioning

confidence: 99%

“…23,29 A tentative diffusion coefficient was calculated considering the convolution model for ECE (electron transfer) reaction mechanism. 29 where A is the electrode area, D CITH is the CITH diffusion coefficient and the other terms have their usual meaning, an average value of (6.77 ± 0.07) × 10 -6 cm 2 s -1 for D CITH was calculated in ACN plus 0.1 mol L -1 TBAP. Convoluted cyclic voltammograms were obtained at three c * CITH with both bare (A = 0.071 cm 2 ) and MWCNT modified GC (A = 0.16 cm 2 ) electrodes.…”

Section: Resultsmentioning

confidence: 99%

“…On the base of different diagnostic criteria discussed in literature for cyclic voltammograms 28,29,31 and simulation though DigiSim ® software, different theoretical reaction mechanisms involving heterogeneous and homogeneous chemical reactions [28][29][30][31][32] were used to perform the fit of CITH experimental cyclic voltammograms, i.e., ECE, DIM2 (radical-substrate coupling), ECEC self-protonation, etc. The best fitting was obtained when the following theoretical mechanism was used to fit experimental voltammograms ( Figure 7):…”

Section: Mechanism Of Electrochemical Reduction Of Cith: Digital Simumentioning

confidence: 99%

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Electrochemical reduction of the mycotoxin citrinin at bare and modified with multi-walled carbon nanotubes glassy carbon electrodes in a non-aqueous reaction medium

Zachetti¹,

Granero²,

Robledo³

et al. 2012

J. Braz. Chem. Soc.

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O mecanismo de redução eletroquímica de citrinina em acetonitrila mais (C 4 H 9 ) 4 NClO 4 0,1 mol L -1 tanto em eletrodo de carbono vítreo (GC) não modificado quanto em eletrodo GC modificado com nanotubos de carbono de paredes múltiplas foi investigado por voltametria cíclica e eletrólise a potencial controlado. Os resultados obtidos permitiram inferir um mecanismo de eletroredução complexo com etapas químicas e eletroquímicas, acopladas à reação inicial de transferência de elétron. Citrinina apresentou pico catódico único que corresponde no mínimo a duas etapas de redução envolvendo um elétron e duas reações químicas homogêneas, segundo mecanismo de autoprotonação do tipo ECEC (transferência de elétron acoplada com aceitação de próton). As reações químicas se originam nas transferências de próton intermolecular do substrato para os seus produtos intermédios básicos de redução, caracterizando um mecanismo de autoprotonação. Análise cinética por procedimentos de simulação de resultados voltamétricos permitiu uma caracterização completa do mecanismo de redução heterogêneo de citrinina.Electrochemical reduction mechanism of citrinin in acetonitrile plus 0.1 mol L -1 (C 4 H 9 ) 4 NClO 4 at both bare and modified with multi-walled carbon nanotube glassy carbon (GC) electrodes was investigated by cyclic voltammetry and controlled potential electrolysis. Results allowed to infer a complex electroreduction mechanism with chemical and electrochemical steps coupled to the initial electron transfer reaction. Citrinin shows a single cathodic peak that corresponds at least to two electron reduction steps and two homogeneous chemical reactions, conforming to an ECEC (electron-transfer coupled with proton acceptance) self-protonation mechanism. The chemical reactions are originated in the intermolecular proton transfers from the substrate to its basic reduction intermediates, featuring a self-protonation mechanism. Kinetics analysis by simulation procedures of voltammetric results permitted a fully characterization of the mechanism of citrinin heterogeneous reduction.Keywords: citrinin, mycotoxins, multi-walled carbon nanotubes, cyclic voltammetry, square wave voltammetry IntroductionMycotoxins are a group of secondary metabolites produced by fungi of different species and have different structural characteristics. 1 Some mycotoxins are carcinogenic, others are immunosuppressive, vasoactive and others can cause central nervous system damage. Sometimes, the same mycotoxin can cause more than one type of toxic effect. 1 Citrinin or (3R, 4S)-4,6-dihydro-8-hydroxi-3,4,5-trimethyl-6-oxo-3H-2-benzopyran-7-carboxylic acid (CITH, Figure 1) was first isolated from filamentous fungus Penicillium citrinum. 2 It is also produced by other species of Penicillium, 3 Aspergillus 4 and Monascus. 5 Electrochemical Reduction of the Mycotoxin Citrinin at Bare and Modified J. Braz. Chem. Soc. 1132 CITH crystallizes in a disordered structure, with both p-quinone and o-quinone tautomeric forms in a dynamic equilibrium in the solid state (Figur...

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“…The applicability of electrochemical techniques to the determination of P4 is well recognised. It is based on reduction of the 3-keto group in ring A of P4 [11].…”

Section: Introductionmentioning

confidence: 99%