Highly sensitive detection of promethazine hydrochloride in water and human urine using flower-like ZnO nanorods supported by GO sheets and Pt nanoparticles

In this study, we developed three-dimensional flower-like stacked zinc oxide (ZnO) nanorods as cores, which were supported by graphene oxide (GO) and decorated with platinum (Pt) nanoparticles. We explored six different combinations of these materials, specifically GO, ZnO, ZnO/GO, Pt/ZnO, (Pt/ZnO)-GO, and Pt-(ZnO/GO), as potential electrochemical sensors for detecting the first-generation antihistamine drug promethazine hydrochloride (PMTZ) in water bodies. We characterized the crystallinity, chemical composition, functional groups, surface morphology, and elemental proportions of these materials using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) analysis. Following this, we investigated these materials further to identify the optimal one for detecting PMTZ using electrochemical techniques. The newly developed Pt/ZnO composite material-based electrochemical sensor demonstrated exceptional performance for electrochemically detecting PMTZ. It achieved an ultra-low detection limit of 1.85 × 10⁻² µM, a wide linear response range from 0.2 to 116.2 µM, and an outstanding sensitivity of 1.59 µA µM⁻¹ cm⁻². Moreover, the developed sensor showed good resistance to interference (with an effect below 13.2 %), high reproducibility (RSD = 1.14 %), repeatability (RSD = 1.18 %), and stability (with an effect below 16.2 %). The real-time practical applicability of the samples was analyzed using actual human urine samples. The sensor exhibited excellent recovery rates (99.3% to 99.6%), indicating the practicality of the newly developed Pt/ZnO composite material for the electrochemical detection of promethazine hydrochloride.