Electrochemical detection of glyphosate and hexaconazole using a nickel-activated carbon/PEDOT composite derived from coffee silver skin

• Biomass-derived composite for pesticide detection via electrochemistry. • Ni-Activated PEDOT/AC boosts electron transfer in sensor performance. • Detects GLY and HEXA with LOD values of 0.8 ppt and 0.6 ppt, respectively. • Shows clear redox peaks for GLY (−0.3 V) and HEXA (−0.1 V) via CV analysis. • Linear detection in low ppt range for environmental safety applications. A composite material derived from coffee silver skin comprising activated carbon (AC), nickel (Ni), and poly(3,4-ethylenedioxythiophene) (PEDOT) was developed for the electrochemical detection of glyphosate (GLY) and hexaconazole (HEXA). The PEDOT matrix facilitates redox activity, AC provides a porous network, and Ni enhances electron movement. Scanning electron microscopy (SEM) revealed a porous globular morphology, and X-ray photoelectron spectroscopy (XPS) confirmed the presence of the desired elements. Electrochemical studies (cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave voltammetry (SWV)) distinct oxidation peaks at −0.3 V (GLY) and −0.1 V (HEXA). The SWV indicated linear responses for GLY (200–1000 ppt) and HEXA (100–600 ppt), with LODs of 0.8 ppt and 0.6 ppt, respectively. A comparison of liquid chromatography–mass spectrometry (LC–MS) data validated the results, highlighting the potential of the composite for advanced pesticide detection in environmental and agricultural applications.