Towards to the improvement of the analytical response in voltammetric sensors based on rigid composites

© 2014 Elsevier B.V. All rights reserved. In order to increase the efficiency of voltammetric transducers we have studied the use of alternative strategies to characterize and optimize the composition of composite electrodes based on graphite and epoxy. The electroanalytical properties such as limit of detection and sensitivity have been improved by optimizing the distribution of the graphite particles inside the composite materials. The composites were characterized and optimized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements. EIS measurements provide information about the electron-transfer rate, the double-layer capacitance, contact resistance and resistance of the solution. These optimized parameters are directly related with the response time, signal-to-noise ratio (limit of detection) and sensitivity, respectively. In addition, morphological and conductance characterization was performed by atomic force microscopy and complemented with scanning electron microscopy. The improvement of the electroanalytical response was evaluated by means of hydrodynamic amperometry measurements using different reference analytes.