Onion based zinc oxide nanoparticles ability as electrochemical sensor

This work describes the preparation of zinc oxide nanoparticles (ZnO NP) from onion extract through a combination of microwave irradiation and muffle furnace in less than 2 h. Characterization with UV-visible, FTIR, and XRD has confirmed successful formation of nanoparticles. TEM analysis displays the nanoparticles to be spherical shaped with an average size of 6.4 mu. The developed ZnO NP film displays good sensing capability of dopamine and had an oxidation potential of + 0.3 V. Under optimized conditions (pH and scan rate), the ZnO NP-GCE is stable even at 500 rpm, showed good linearity in sensing dopamine within the tested range of 3.9-250 mu M, has a limit of detection of 3.53 mu M and stable electrocatalytic activity even after 30 cycles. The newly developed electrode can distinguish dopamine in a satisfactory way in presence of ascorbic acid and glucose and with 94.9 % of detection in human urine. This study also highlighted the potential of IO Rodeostat (an open source electrochemical workstation) as a feasible option in low resource laboratories to perform sensing studies.