This study presents an electrochemical sensor developed from a glassy carbon electrode modified with nanodiamond film (ND/GCE). This electrochemical response of the proposed sensor was improved, and it showed excellent analytical performance for the detection of paracetamol (PAR), which was attributed to the high PAR charging capacity on the electrode surface and the excellent electrical conductivity of ND. Morphological and electrochemical characterizations of the sensor were performed via scanning electron microscopy (SEM) and cyclic voltammetry using a redox probe [Fe(CN)6]3−. The sensor was applied for the determination of PAR. Quantification was performed using square-wave voltammetry, and it showed a linear concentration range from 0.79 to 100 µmol L−1, with a limit of detection of 0.18 µmol L−1. The proposed sensor exhibited satisfactory repeatability and high sensitivity in the determination of the analyte of interest. The electrochemical sensor was also employed for the analysis of PAR in real samples, with recovery rates ranging between 96.4 and 98.7%. This sensor was successfully used for the determination of the drug in pharmaceutical samples.
