Development of Sonogel-Carbon based biosensors using sinusoidal voltages and currents methods

In this work, biosensors based on Sonogel-Carbon electrodes modified with poly(3,4-ethylenedioxythiophene) - tyrosinase biocomposite materials have been developed using sinusoidal voltages and currents methods The sinusoidal voltages method uses a sinusoidal voltage signal of a 50 mHz fixed frequency and high amplitude superimposed on a direct current potential to modify the Sonogel-Carbon electrodes surface with the poly(3,4-ethylenedioxythiophene) - tyrosinase layer. A new preparation method involving the application of a sinusoidal current signal with fixed frequency and amplitude over a direct current has been developed as well. The experimental parameters of these methods have been optimized and selected in such a way to highlight the contribution of the sinusoidal component in the biosensors preparation. The advantages of the new preparation methods in terms of electrocatalytic and analytical efficiencies are presented. The analytical performances of the proposed biosensors towards benchmark analytes like dopamine, hydroquinone, and catechol have been investigated. The lowest limit of detection value of 7.10 μM and a high sensitivity value of 0.0037 μA/μM for dopamine determination were obtained with a biosensor prepared via the new sinusoidal currents method. The biosensors were successfully applied in the quantification of dopamine in pharmaceutical products.