Synthesis and Characterization of MWNTs/Au NPs/HS(CH₂)₆Fc Nanocomposite: Application to Electrochemical Determination of Ascorbic Acid

Abstract

In this article, a detailed electrochemical study of a novel 6-ferrocenylhexanethiol (HS(CH 2 ) 6 Fc) self-assembled multiwalled carbon nanotubes-Au nanoparticles (MWNTs/Au NPs) composite film was demonstrated. MWNTs/Au NPs were prepared by one-step in situ synthesis using linear polyethyleneimine (PEI) as bifunctionalizing agent. HS(CH 2 ) 6 Fc, which acted as the redox mediator, was self-assembled to MWNTs/Au NPs via Au-S bond. Transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), Fourier transformed infrared absorption spectroscopy (FT-IR), UV-visible absorption spectroscopy, and cyclic voltammetry were used to characterize the properties of the MWNTs/Au NPs/HS(CH 2 ) 6 Fc nanocomposite. The preparation of the nanocomposite was very simple and effectively prevented the leakage of the HS(CH 2 ) 6 Fc mediator during measurements. The electrooxidation of AA could be catalyzed by Fc/Fc þ couple as a mediator and had a higher electrochemical response due to the unique performance of MWNTs/Au NPs. The nanocomposite modified electrode exhibited excellent catalytic efficiency, high sensitivity, good stability, fast response (within 3 s) and low detection limit toward the oxidation of AA at a lower potential.

Electrochemical sensors with carbon nanotubes for biomedical research

“…Study of the characteristics of the sensor by cyclic voltammetry showed a high sensitivity in the oxidation of ascorbic acid. The sensor was character ized by a reading time of approximately 3 s, stable readings, decreased oxidation potential of ascorbic acid, and relatively low detection limit for this compound [78].…”

Electrochemical sensors based on carbon nanotubes and their use in biomedical research.Part 2: sensors manufactured by dispersion of carbon nanotubes by means of polyethyleneimine, organic dyes, cyclodextrins, chitosan, proteins, room-temperature ionic liquids, gels, and thiols. Sensors manufactured by dispersion of carbon nanotubes by electropolymerization process. sensors manufactured by dispersion of carbon nanotubes by layer-by-layer deposition

“…Представленные сведения позволяют сделать следующие выводы. Технологии изготовления электрохимических сенсоров путём нанесения углеродных нанотрубок на рабочую поверхность электрода с помощью полиэтиленимина [2][3][4][5][6][7], органических красителей [9,[11][12][13] и циклодекстринов [14][15][16][17] схожи между собой: нанотрубки распределяются в растворах перечисленных химических соединений, образуя гомогенную суспензию, которая далее наносится на поверхность электрода с последующим высыханием. Хитозан [18][19][20][21][22], белковые соединения [23,24], ионные жидкости [25,26], гели [27,28] и тиолы [29][30][31] также могут использоваться для нанесения углеродных нанотрубок на рабочую поверхность стеклоуглеродного, золотого или др.…”

“…Получаемые сенсоры позволяют определять большое число химических соединений, являющихся характерными для биомедицинских исследований, в частности дофамин [2-4, 11, 15, 19, 26, 43], допак [2,4], адреналин [4,15,35], норадреналин [4,17,20], аскорбиновая [2,7,19] и мочевая [16,20] кислоты, пероксид водорода [2,4,5,22,25,[27][28][29][36][37][38], NADH [21,44], глюкоза [2,21,22,28,29,[36][37][38][39]44], фруктоза [44], холестерин [27], цитохром с [30], амитрол [4,5], диурон [5], монурон [5], хлортолурон [5], офлоксацин [12], эстрадиол [13], тимин …”

“…Исследование характеристик сенсора методом циклической вольтамперометрии показало высокую чувствительность при окислении аскорбиновой кислоты. Сенсор характеризовался временем установления показаний около 3 с, стабильностью показаний, пониженным электрическим потенциалом окисления аскорбиновой кислоты, а также достаточно низким пределом обнаружения этого химического соединения [7].…”

A Label‐Free Amperometric Immunosensor Based on Redox‐Active Ferrocene‐Branched Chitosan/Multiwalled Carbon Nanotubes Conductive Composite and Gold Nanoparticles

“…Ferrocene and its derivatives, which are well-known substances as mediators due to their relatively low molecular mass, good electrochemical reversibility, regeneration at low potential, and high chemical stability, have been widely used to manufacture electrochemical sensor and biosensor [16][17][18]. However, there are several challenges concerning immobilization of electron-shuttling mediators on electrode surfaces, especially for soluble mediators with low molecular weight which can easily diffuse away from the electrode surface into the bulk solution, resulting in poor sensor response performance.…”