A molecularly imprinted polymer (MIP) was developed for the electrochemical determination of the antiviral drug
sofosbuvir (SOF). The MIP was obtained by polymerization of p-aminothiophenol (p-ATP) on N,S co-doped
graphene quantum dots (N,S@GQDs) in the presence of gold nanoparticles to form gold-sulfur covalent network.
The presence of quantum dots improves the electron transfer rate, enhances surface activity and amplifies the signal.
The nanocomposites were characterized by FTIR, TEM, EDX, and SEM. The electrochemical performance of the
electrode was investigated by differential pulse voltammetry and cyclic voltammetry. The sensor uses
hexacyanoferrate as the redox probe and is best operated at a potential of around 0.36 V vs. Ag/AgCl. It has a
linear response over the concentration range of 1–400 nM SOF, with a detection limit of 0.36 nM. Other features
include high selectivity, good reproducibility and temporal stability. The sensor was applied to the determination of
SOF in spiked human plasma.