Ferrocene-Containing Gallic Acid-Derivative Modified Carbon-Nanotube Electrodes for the Fast Simultaneous and Selective Determination of Cytostatics from Aqueous Solutions

Abstract

In this work, a ferrocene-containing gallic acid-derivative modified carbon-nanotube paste electrode (Gal-Fc-CNT), obtained through simple mechanical mixing, was studied for the fast simultaneous voltammetric determination of doxorubicin (DOX), capecitabine (CPB), and cyclophosphamide (CPP) as cytostatic indices based on their cumulative signals and the selective determination of DOX. The individual and simultaneous electrochemical behavior of DOX, CPB, and CPP, studied through cyclic voltammetry (CV) on the Gal-Fc-CNT paste electrode at various pHs and potential ranges, allowed for the development of a simple simultaneous determination method as a cytostatic index at a pH of 12 using square-wave voltammetry, which allowed for a better performance than reported electrodes for each individual cytostatic. A faster and selective detection of DOX, with a limit of detection of 75 ng·L−1, was achieved using square-wave voltammetry at a pH of 3. The good results obtained for the real tap water assessment indicated the applicability of the Gal-Fc-CNT paste electrode for practical applications (water samples).