A novel electrochemical nanosensor based on NH2-functionalized multi walled carbon nanotubes for the determination of catechol-orto-methyltransferase inhibitor entacapone

•Surface area of modified electrode was 3 times higher than bare GCE surface.•Surface morphology of designed sensor was determined by SEM-EDX analysis.•NH2fMWCNT/GCE gives approximately 25times higher response than bare GCE for ENP.•The ENP was successfully detected in concentration range of 1–50 nM with LOD of 1.453 × 10−11.•The RSD% values for repeatability, reproducibility and stability was less than 2%. In this study, an antiparkinson drug Entacapone (ENP) is electrochemically investigated under optimized conditions using NH2 functionalized multi walled carbon nanotubes (NH2fMWCNT) decorated over glassy carbon electrode (GCE). The surface morphology of the NH2fMWCNT/GCE was probed by scanning electron microscopy (SEM) armed with EDX analysis. Electrochemical impedance spectroscopy (EIS) was employed to investigate the electron transfer capability of modified and bare electrodes. Cyclic voltammetry was used to compare the redox response of ENP on the surface of modified and unmodified electrodes. The influence of interfering agents was also studied to examine the selectivity of the designed sensor. For the purpose of practical applicability of the proposed method, differential pulse voltammetric method was applied for the investigation of ENP in real samples i.e., tablet, human serum and urine. Almost 100% recovery percentages were obtained from tablet, serum and urine samples with RSD% values of less than 2% for all the samples, thus, suggesting promising applicability of the designed electrochemical sensing platform (NH2fMWCNT/GCE) for determination of ENP in pharmaceutical dosage and real samples.