Adsorptive Stripping Voltammetric Determination of 2,4‐Dichlorophenol by Laponite Modified Carbon Paste Electrode

• Published in: Electroanalysis (New York, N.Y.) Vol. 33; no. 3; pp. 695 - 704
• Main Authors: Stoytcheva, Margarita, Zlatev, Roumen, Velkova, Zdravka, Gochev, Velizar, Ayala, Alan, Montero, Gisela, Valdez, Benjamín
• Format: Journal Article
• Language: English
• Published: 01-03-2021
• Subjects: 2,4-dichlorophenol; Adsorption studies; Adsorptive stripping voltammetry; Laponite modified carbon paste electrode
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.202060444

A laponite modified carbon paste electrode was prepared, characterized and applied for the 2,4‐dichlorophenol (2,4‐DCP) voltammetric determination. It takes advantage of the ability of laponite to adsorb phenols, as well as of its availability and very low cost. Kinetic and equilibrium data for 2,4‐DCP adsorption by laponite in aqueous dispersions demonstrated that the adsorption process obeyed a pseudo first order kinetic model and was consistent with the formation of adsorbed multilayers on a surface with heterogeneous pore distribution. The composite paste electrode exhibited a heterogeneous surface with 65 % increased surface area and 27 % enhanced catalytic activity compared to the unmodified one. The adsorptive stripping voltammetric determination of 2,4‐DCP at an electrode with an optimized graphite:laponite ratio of 55 : 15 w% using a 3 min accumulation time at pH 5.5 was found to be suitable for its quantification in the linear concentration range extended up to 50 μmol L−1 with a sensitivity of 0.56 μA L μmol−1 and a LOD of 0.2 μmol L−1 (S/N=3).The 2,4‐DCP electrochemical response was not affected by the presence of some structurally similar phenols, like catechol and p‐nitrophenol, while resorcinol, 2‐chlorophenol, and 4‐chlorophenol presented interferences. The results were validated by 2,4‐DCP determination in spiked tap water.