Daclatasvir (DAC) is listed on the World Health Organization's list of essential medicines needed in a basic health system, therefore, electrochemical and impedance spectroscopic methods are necessary to obtain information about its mechanism using a carbon paste electrode (CPE) modified with chitosan (Cs)/multi-walled carbon nanotubes (CNT) and cobalt nanoparticles (CoNps). The simultaneous determination of DAC with the hepatitis B antiviral drug entecavir (ENT) was also investigated by differential pulse voltammetry in universal buffer pH 2.0. The experimental results specify a linear relation between the DAC peak current and its concentration in the range from 1.0 nM to 12 μM, leading to a detection limit of 8.82 × 10−10 M. Finally, this novel sensor was successfully used to determine DAC in human biological fluids such as urine, blood serum and in pharmaceutical formulations.
