Disposable sensor based on carbon electrodes modified with cobalt-doped titanium dioxide nanocrystals for electrochemical detection of amoxicillin

Abstract

In this study, we propose the combination of stencil-printed carbon electrodes (SPCE) and a new nanocomposite based on titanium dioxide-cobalt (1.0 w/w %) (TiO2-1%Co) for the analysis of Amoxicillin (AMX) in pharmaceutical samples. The modification process by drop casting approach of the SPCE was performed with TiO2-1%Co and provided an increase in analytical sensitivity. Detailed morphological, structural, and electrochemical characterizations of the electrodes surface were investigated. The results obtained from characterization showed that the TiO2-1%Co nanocrystals were distributed on the surface of the carbon electrode. The detection of AMX (pH 7.0) was performed with square wave voltammetry using optimized conditions and resulted in a satisfactory linear response (R2 = 0.99) in the range of 20 to 150 μmol L−1, and the estimated limits of detection and quantification were 5.8 μmol L−1 and 19.5 μmol L−1, respectively. Repeatability studies (intra-day and inter-day) of modified electrodes revealed relative standard deviation values ranging from 5.8 to 8.1%. The selectivity of the proposed sensor indicated an acceptable interference (lower than 5%). Additionally, the results obtained with TiO2-1%Co/SPCE for real pharmaceutical samples were compared with UV–Vis Spectroscopy, and was possible to infer that the analytical responses were adequate concerning the labeled values, there are no statistical differences between the reference analysis and the proposed electrochemical method with a confidence level of 95%. The modified electrode offered some advantages such as a disposable sensor, low cost, low sample volume, high repeatability, and reproducibility. The proposed combination of SPCE modified with novel TiO2-1%Co nanocrystals is an attractive strategy for AMX analysis.