Електрохімічне відновлення вітаміну В1 на наноструктурованій поверхні нікелю

Abstract

Вольтамперометричним методом досліджено процес eлектрохімічного відновлення вітаміну В1 (тіамін броміду) на поверхні наноструктурованого нікелевого електрода. З’ясовано, що інтенсивність розряду тіамін броміду на нано-структурованому електроді значно вища, ніж на гладкому. На підставі отриманих результатів розраховано кінетичні константи процесу електровідновлення та запропоновано співвідношення, які допоможуть кількісно визначати вміст тіамін броміду в розчинах. Ключові слова: наноструктурований електрод, тіамін бромід, вольтамперометрія .

Vitamin В1 (thiamine bromide) is a component of the ferments, which take part in the exchange of substances flowing in live organisms and has a wide application in medical practices for medical treatment of different nerve illnesses. Voltammetry is one of the most universal electrochemical methods for investigation and detection of organic substances. As known voltammetry is characterized by simplicity, sensitivity, cost – efficiency, precision, accuracy and may be recommended for development a chemosensors for qualification analysis of vitamins and proteins in food products, biosystems, technological analysis of the run-off waters and in the medicine industry. Many investigations of the last year is devoted to polarograph investigations of the vitamin water solution by means of toxic mercury or expensive platinum electrodes, while electrochemical behavior of thiamine bromide on the nanostructured electrode does not study. In the present paper the electrochemical process of the vitamin B1 reduction on the nickel nanostructural electrode was investigated by voltammetric method. As indicator electrodes the smooth and nanostructured nickel electrodes by similar work area have been used. Nanostructured nickel electrode of the type “cluster – globule – surface” was fabricated in the shape of nickel plate with deposited from one side of plate uniform nanostructured elements in the vive of cones with height and radius of curvature near the peak of 50 nm. An area of the visible work electrode surfaces was 0.2375·10-4 m2 . A surface concentration of elements in massive achieves 109 m-2 . As a counter electrode a platinum wire with visible surface of 7·10-4 m2 was used. A saturated silver-chloride electrode Ag/AgCl was used as a reference. Obtained in cyclic and linear voltammograms indicate that vitamin B1 (thiamine bromide) electrochemically reduces on both smooth and nanostructured nickel electrodes. The electrochemical reduction of vitamin B1 on the nickel nanostructural electrode starts at the potential Е > 0,5 V and achieves a maximum in the interval of Е = - (0,92...0,97) V. Process of thiamine bromide electroreduction on the electrode with nanostructured surface is significantly lighting, potential of the cathode maximum shifts on 0.1 V in positive direction as compared with smooth nickel electrode at the same concentration of thiamine bromide in solution, which may be explained by electrocatalytic action of nanostructured electrode surface. Existence of a single clear maximum on the cathode branch line of potentiodynamic curves may be evidence to one step of electroreduction and suggested its one electron character. Increasing a rate of potential sweeping is accompanied by rising of reduction current and shifting of peak potential to the negative side which causes amplification of irreversibility of the process. As optimal sweep rate a value of 5·10-2 V/s was chosen. It claims that thiamine bromide has significantly higher discharge intensity on the nanostructural nickel electrode than on the smooth one. On the basis of obtained results the kinetic parameters of thiamine bromide reducing process were calculated. It proposed the linear equations which make it possible to quantify identification the thiamine bromide concentration in the solution. As alternative to polarograph detection of vitamin, we propose a voltamperometric chemosensor where nanostructured surface of nickel is used as indicator electrode it claims that thiamine bromide has significantly higher discharge intensity on the nanostructural nickel electrode than on the smooth one in 2-3 times and increases in the factor of tens as compared with mercury electrode. This significantly increases a sensitivity of sensor and make it application more safe. Key words: nanostructural electrode, thiamine bromide, voltammetry.

Вольтамперометрическим методом исследован процесс электрохимического восстановления витамина В1 (тиамин бромида) на поверхности наноструктурированного никелевого электрода. Установлено, что интенсивность разряда тиамин бромида на нано-структурированном электроде значительно выше, чем на гладком. На основе полученных результатов рассчитаны кинетические константы процесса электровосстановления и предложены соотношения, позволяющие количественно определять содержание тиамин бромида в растворах. Ключевые слова: наноструктурированный электрод, тиамин бромид, вольтамперометрия.