Green and cost-effective voltammetric assay based on activated glassy carbon electrode for determination of the plant growth regulator methyl jasmonate

A green, cost-effective, and efficient square-wave voltammetric (SWV) assay based on an electrochemically activated glassy carbon electrode (aGCE) for the determination of the plant growth regulator methyl jasmonate (MeJA) was developed. The activation was performed by anodization in 0.1 mol L⁻¹ NaOH by 5 cyclic voltammetric measurements in the potential range of 0–2 V at a scan rate of 100 mV s⁻¹. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) were applied to analyze the difference between the bare GCE and the aGCE in terms of their electrochemical properties. The functionalization of the GCE surface by oxygen-containing groups not only creates new active sites but also improves electron transfer dynamics and electrocatalytic activity. The SWV procedure displays a wide linear response from 0.1 to 50.0 μmol L⁻¹, a low LOD = 0.027 μmol L⁻¹, and LOQ = 0.097 μmol L⁻¹. The aGCE was successfully applied to MeJA analysis in Phaseolus coccineus leaf extracts.