Poly(caffeic acid) Redox Couple Decorated on Electrochemically Reduced Graphene Oxide for Electrocatalytic Sensing Free Chlorine in Drinking Water

Regular water quality measurements are essential to the public water supply. Moreover, selective free chlorine (disinfectant) level monitoring without an interfering agent is necessary. The present work aimed to fabricate poly(caffeic acid) (p-CFA) coated on an electrochemically reduced graphene oxide (ERGO) surface for the selective detection of free chlorine. Electron microscopy and various spectroscopic techniques confirmed the p-CFA@ERGO/glassy carbon (GC) electrode. The p-CFA@ERGO/GC coated probe surface coverage was calculated to be 4.75 x 10(-11) mol cm(-2). The p-CFA@ERGO/GC showed superior catechol/o-quinone oxidation/reduction peaks for electrocatalytic free chlorine determination. The performance of the developed sensor electrode was outstanding, with an extensive range of free chlorine detection (20 mu M to 20 mM), high sensitivity (0.0361 mu A mu M-1), and low detection limit (0.03 mu M). The p-CFA@ERGO/GC capability of the realist water samples, such as the tested commercial and tap water, yielded a good range of recovery (from 98.5% to 99.9%). These values align with the standard N,N '-diethyl-p-phenylenediamine reagent method results.

Automated summary

This study aimed to develop a poly(caffeic acid) (p-CFA) coated electrochemically reduced graphene oxide (ERGO) surface for selective detection of free chlorine. The p-CFA@ERGO/GC electrode exhibited superior electrocatalytic performance for free chlorine determination, with a wide detection range (20 μM to 20 mM), high sensitivity (0.0361 μA μM-1), and low detection limit (0.03 μM). The p-CFA@ERGO/GC electrode demonstrated good recovery for real water samples such as commercial and tap water, consistent with the results of the standard reagent method.