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Modified electrode with application in the detection of catechol from aqueous solutions

Authors: Maria Coroș, Stela Pruneanu, Florina Pogăcean, Lidia Măgerușan, Crina Anca Socaci, Marcela Roșu

Keywords: catechol, electrochemical detection, graphene-porphyrin modified electrode

Applications

Graphene-based composite modified electrodes are new, modern products that have many advantages over conventional electrodes and therefore find high-tech applications in electrochemical sensors and gas sensors, respectively. The electrode developed by our group is integrated into an electrochemical cell that is coupled to a potentiostat and is used to test the quality of domestic water, drinking water or wastewater by electrochemical detection of toxic phenolic compounds: hydroquinone and catechol.

Innovative aspects

Catechol, used in cosmetics, medicines, pesticides, flavoring agents and dyes, is a toxic chemical and therefore a pollutant.

Its detection and quantification from wastewater is hampered by the fact that the electrochemical oxidation signal of catechol (1,2-dihydroxybenzene) overlaps with that of hydroquinone (1,4-dihydroxybenzene) when using unmodified electrodes.

For this reason we have developed new, modified electrodes that allow easy and accurate detection of these compounds. The graphene-modified electrodes have proven to be very efficient for the detection of catechol.

Technology

A new type of composite material based on graphene and 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) was prepared by a simple procedure involving electrochemical exfoliation of a graphite bar in aqueous solution (0.2 M KCl) containing TPyP.

The resulting material was used to modify the surface of a glassy carbon electrode.

Sensitivity, selectivity and reproducibility of the modified electrode for catechol detection were evaluated by cyclic voltammetry measurements.

Advantages

  • The electrode has an increased active area (three times greater than the unmodified electrode) and improved electrocatalytic properties (the electrochemical signal is doubled and the oxidation potential is decreased by 250 mV compared to the unmodified electrode)
  • The modified electrode has been successfully applied for the detection of catechol in wastewater: detection limit 3 × 10-7 M; linear range 10-6-10-4 M; sensitivity 3.22 A/cm2
  • All specifications are far superior to the unmodified electrode

Patent

Patent 132196/ 30.07.2021

Title: Electrochemical preparation process of a new composite material based on graphene and porphyrin and its application
Inventors: Coroș Maria, Socaci Crina-Anca, Pruneanu Stela-Maria, Pogăcean Florina, Roșu Marcela-Corina, Măgerușan Lidia