The mechanism for the electrooxidation of procarbazine pharmaceutical preparation in alkaline media and its mathematical description

The mechanism for the electrooxidation of procarbazine in alkaline media has been proposed. The process is realized completely on the electrode surface and is adsorption-controlled. The oscillatory behavior in this case is more probable, than for neutral media and may be caused by influences of electrochemical oxidation and salt dissolution from the electrode surface

Математическое описание «политиофенового парадокса» для потенциостатической электрополимеризации электрохимически модифицированных тиофенов

The phenomenon of "polythiophene paradox" for insoluble polythiophenes based on electrochemically modified monomers has been described theoretically. The corresponding mathematical model was examined using linear theory of stability and bifurcation analysis. Stability conditions of steady state, monotonic and oscillatory instabilities have also been obtained.Явление «политиофенового парадокса» для нерастворимых политиофенов на основе электрохимически модифицированных мономеров было описано теоретически. Соответствующая математическая модель была рассмотрена с помощью линейной теории устойчивости и бифуркационного анализа. Условия устойчивости стационарного состояния, монотонной и автоколебательной неустойчивостей также были получены

The Theoretical Description for a Sucralose Electrochemical Cathodical Determination over a 9-9´-Diacridyl-modified Electrode

A novel electroanalytical process for sucralose determination has been theoretically suggested. Sucralose is immobilized over an acridine derivative 9-9´-diacridyl, yielding a quaternary salt, which is thereby gradually electrochemically reduced to an N-N´-disubstituted acridone derivative. The correspondent mathematical model has been developed and analyzed by means of linear stability theory and bifurcation analysis, and this analysis has shown the high probability of the oscillatory and monotonic instabilities, due to the double electric layer structure changes during all of the stages of the process. Nevertheless, it also confirms the efficiency of 9-9´-diacridyl-modified electrode for sucralose determination in an electroanalytical system, which may be coupled with a fluorescent indicator. DOI:  http://dx.doi.org/10.17807/orbital.v13i3.158

A detecção eletroquímica da lidocaína sobre o oxihidróxido de cobalto trivalente. Uma possibilidade teórica a ser avaliada

O comportamento eletroquímico da lidocaína durante a sua eletrooxidação sobre o oxihidróxido de cobalto trivalente em meio levemente básico, realizada para fins eletroanalíticos, foi avaliado do ponto de vista mecanístico matemático. Da análise foi feita uma conclusão acerca do desempenho do CoO(OH) como modificador de elétrodo na eletrooxidação da lidocaína in vivo e in vitro. Foi, outrossim, verificadaa possibilidade da realização das instabilidades oscilatória e monotônica no sistema.The electrochemical behavior of lidocaine during its electrooxidation over trivalent cobalt oxyhydroxide in lightly alkaline medium, realized for electroanalytical purposes, was evaluated from the mechanistic mathematical point of view. From analysis a conclusion has been made of the electroanalytical function of CoO(OH)as an electrode modifier for lidocaine electrooxidation in vivo and in vitro. Also, the possibility of oscillatory and monotonic instabilities has been verified in the system

The Theoretical Description for Chlorantraniliprole Electrochemical Determination, Assisted by Squaraine Dye – Nano-CuS Composite

The theoretical description for the chlorantraniliprole electrochemical determination, assisted by the hybrid composite of squaraine dye with CuS nanoparticles has been described. The correspondent reaction mechanism has been proposed, and the correspondent mathematical model has been developed and analyzed by means of linear stability theory and bifurcation analysis. It has been shown that the chlorantraniprole electrochemical anodical determination on high potential may be efficiently provided by cupper sulfide nanoparticles, stabilized by the squaraine dye. On the other hand, the oscillatory and monotonic instability is also possible, being caused by DEL influences of the electrochemical stage. DOI: http://dx.doi.org/10.17807/orbital.v13i3.151

Electrochemical Determination of Sudan Dyes and Two Manner to Realise it a Theoretical Investigation

In this work, a general theoretical description of the electrochemical determination of Sudan dyes by cathodic and anodic route has been made. Two mathematical models have been developed for each case, being, afterward, analyzed by means of linear stability theory and bifurcation analysis. It has been shown that in both cases, the systems are efficient from the electroanalytical point of view. The possibility for the oscillatory and monotonic instability has also been verified

Theoretical Description for Omeprazole Cathodical Electrochemical Determination, Assisted by Omeprazole Electrochemical Determination, Assisted by the Composite Poly(1,2,4-triazole) – VO(OH)

Abstract: In this work, we describe theoretically the possibility of omeprazole electrochemical determination, assisted by the composite containing vanadium oxyhydroxide as an active substance and the polymer of 1,2,4-triazolic derivative as a mediator. The omeprazole molecule undergoes a sulfoxide to sulfide reduction process over a trivalent vanadium compound. The vanadium oxyhydroxide, at its turn, may be oxidized to a tetravalent state, represented in two forms. The electroanalytical process behavior will be illustrated by a trivariate equation-set, analysis of which confirms the efficiency of the composite of poly (1,2,4-triazole) with VO(OH). Vanadium (III) oxyhydroxide may be efficiently used for omeprazole detection both in pharmaceutical formulations, food, and biological liquids

The Mathematical Modeling for CoO(OH) – Poly(5-Amino-1,4-Naphthoquinone) Composite-Based Sensor for 1-Propenesulfenic Acid and Propanethial S-Oxide Detection in Food and Lacrimogenic Compositions

Abstract: The theoretical description for 1-propenesulfenic acid and its isomer propanethial-S-oxide, substances, responsible for leek lacrimogenic activity, has been described theoretically. The process is realized anodically over a poly(naphthoquinone) – CoO(OH) composite. A model has been developed and analyzed using linear stability theory and bifurcation analysis. According to the model analysis, the ionic compound's transformation during the sulfenic acid oxidation may be responsible for the oscillatory and monotonic instability alongside the double electric layer (DEL) influences of the electrochemical stage. Nevertheless, the model's analysis shows that the electroanalytical process is efficient for determining both of the analytes