Facile electro-activated glassy carbon electrodes (e-GCEs), which are prepared in electrolyte solution with certain potential for seconds, have been verified to improve analytical performance toward not a few electro-active molecules recently. Nevertheless, how and why the potential plays an important role is not clear, and even not receive enough consideration. In this paper, we found that the mode and the range of applied potential significantly impacted the sensitivity of methyl parathion (MP), which is a typical pesticide with electro-active group of -NO2. Compared with constant potential, the e-GCE with cyclic potential provided much more stable baseline during MP detection. Additionally, the electro-oxidation peak current of MP at around -0.1 V on it was higher than another changeable potential (constant current). What’s more interesting, with cyclic potential for 50 segments from -2 to 1.5 V, the peak current value increased by 30 times in comparison with bare GCE, while only 2 times from -2 to 1 V. Then after systematical investigation including structures of electrodes surface and functional groups, we speculated that the produced group of O-C=O in the process of activation and remained groups of C-O and C=O on bare GCE surface is beneficial to adsorb MP molecule leading to enhanced peak current. Employing the proposed e-GCE, the limit of detection of MP achieved to 0.015 μM and the reproducibility is perfect. This work elucidates the potent impact of electro-activation potential parameters on electroanalysis perform.

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