Acid Pre-Treatment of Graphite Electrodes: An Alternative to Enhance the Sensing Performance of Benzenediol Isomers

Electroanalytical techniques offer several advantages: low cost, portability, and high analysis frequency. These benefits can be further enhanced by replacing standard electrodes (boron-doped diamond, glassy carbon, gold, platinum, etc.) with abundant, low-cost carbon materials. Pyrolytic Graphite Sheet (GS) electrodes have recently emerged as a reliable alternative, providing good stability, sensitivity, and mechanical strength. Their performance can be improved with acidic treatments. Scanning electron and atomic force microscopy images revealed irregular patterns on the edges of acid-treated GS, consistent with Raman spectra, which showed changes in the ID/IG ratio, indicating more structural defects. The acidic treatment also increased the electroactive area of GS electrodes and oxygen-containing functional groups, as observed by XPS, leading to enhanced signal currents. Additionally, electrochemical impedance spectroscopy confirmed a decrease in charge transfer resistance. Treated electrodes exhibited lower detection limits for catechol (0.58 μmol l −1 ) and resorcinol (0.16 μmol l −1 ) compared to untreated GS electrodes. The presence of potential interferents, such as KCl, NaCl, glucose, ascorbic acid, ibuprofen, paracetamol, and uric acid, did not affect the detection of catechol and resorcinol. Recovery values for spiked water samples ranged from 80% to 109%, confirming the accuracy of the proposed analytical method.