Morphological evolution of nanosheets-stacked spherical ZnO for preparation of GO-Zn/ZnO ternary nanocomposite: A novel electrochemical platform for nanomolar detection of antihistamine promethazine hydrochloride

•Nanomolar-level detection of hazardous antihistamine promethazine hydrochloride.•GO-Zn nanohybrid complex is synthesized and used for the first time in electrochemical sensing.•Morphologically controlled preparation of nanosheets-stacked novel spherical ZnO.•Proposed PMTZ sensor exhibited ultra-low detection limit and wide linear concentration range.•Practical feasibility analysis using biological samples, pharmaceutical tablets, and river water. [Display omitted] This work focuses on the nanomolar-level detection of the antihistamine, promethazine hydrochloride (PMTZ), based on a novel ternary nanocomposite sonochemically prepared using a zinc-graphene oxide (GO-Zn) complex and a nanosheets-stacked spherical ZnO. The efficient detection of PMTZ is very important because of its critical side effects when overdosed and its high toxicity to aquatic life. Morphologically varied ZnO nanostructures (spindle-like, nanosheets-stacked spherical, nanoplates-based spherical, and rod-flower) were synthesized using a new aqueous solution approach by regulating the concentration of base in the reaction mixture. Characterization techniques including SEM, TEM, elemental mapping, XRD, Raman spectroscopy, and XPS were utilized for analyzing the properties of synthesized materials. Electrochemical investigations employing cyclic voltammetry and differential pulse voltammetry techniques showcased outstanding electrocatalytic activity of the proposed ternary nanocomposite-modified screen-printed carbon electrode towards PMTZ detection. The PMTZ sensor attained ultra-low detection limit of 0.3 nM, broad linear range from 0.05 to 177.45 µM, and a sensitivity of 5.29µAµM−1cm−2. Furthermore, good operational stability, anti-interference, repeatability, and reproducibility was exhibited by the developed sensor. The real sample analysis provided excellent recovery results indicating outstanding practicability of PMTZ detection.