An electrochemical sensor based on plasma-treated zinc oxide nanoflowers for the simultaneous detection of dopamine and diclofenac sodium

In this paper, an oxygen plasma-treated ZnO nanoflower-based screen-printed electrode (SPE) is proposed as an electrochemical sensor for the simultaneous detection of dopamine (DA), and diclofenac sodium (DS). Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were applied to characterize the morphology and structure of the nanomaterials. The ZnO nanoflowers with a large specific surface area exhibited good electrochemical performance, and they were conducive to ion exchange. The electrochemical behaviors of DA, and DS were evaluated by cyclic voltammetry in the potential range of 0.3-1 V; the linear response ranges were 0.1-300, and 0.01-40 mu M, and the sensitivities were 0.26, and 0.37 mu A.mu M-1 cm(-2), respectively, with detection limits of 0.28, and 0.11 mu M. The selective detection of DA, and DS was evaluated in the presence of other compounds. The results revealed that the oxygen plasma-treated ZnO/SPE, as an electrochemical sensor, could simultaneously detect these substances with good stability and low detection limit. The proposed method was successfully applied using urine samples, and has a good recovery rate. In the future, it may serve as a new detection technology for drug detection and health monitoring.