Synthesis of Polypyrrole-Graphene Oxide (PPy/GO) from Deep Eutectic Solvent and Its Characterization for Determination of Metronidazole Pharmaceutical Substance Using Spectrofluorometric Technique

A polypyrrole-graphene oxide (PPy/GO) nanocomposite was made chemically using a polymerization method in deep eutectic solvents made up of choline chloride and propionic acid in a 1:2 molar ratio. The purpose of this study is to examine the feasibility and efficacy of PPy/GO nanocomposite in the detection of metronidazole in pharmaceutical formulations utilizing spectrofluorometric techniques. Characterization of the synthesized PPy/GO nanocomposite was conducted using several methods such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and X-ray diffraction (XRD). The optimal parameters such as pH buffer solution, potential interferences, reaction duration, concentrations of metronidazole, and interference, and test in real sample were examined. Under the established ideal conditions, the curve of calibration exhibited a linear range of 0.3–20 µg/mL, with a correlation coefficient (R²) of 0.98712. The limit of detection (LOD) was 0.09 µg/mL, while the limit of quantification (LOQ) was 0.29 µg/mL. The relative standard deviation (RSD) readings for five replicates of three metronidazole standard solutions (0.3, 10, or 20 µg/mL) were assessed, yielding RSD percentages ranging from 1.29% to 2.34% and error percentages from −3.33% to 1.20%, thereby demonstrating the method's precision and accuracy. This study provides a viable and useful way to detect metronidazole in pharmaceutical samples. Moreover, the data indicate that PPy/GO may constitute a novel category of fluorescence quenching reagent for medicinal applications. This approach is effective for regular analysis and quality control assays because of its relative freedom from interferences.