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Preconcentration and Successful Selective Detection of Traces of Diclofenac in Water using a Nanostructured Modified Carbon Paste Electrode
Author(s) -
Amra Siham,
Bourouina Mustapha,
Bourouina Bacha Saliha,
Hauchard Didier
Publication year - 2021
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.202060415
Subject(s) - detection limit , materials science , electrode , adsorption , horizontal scan rate , carbon nanotube , carbon paste electrode , graphite , electrochemical gas sensor , electrochemistry , analytical chemistry (journal) , voltammetry , scanning electron microscope , carbon fibers , nuclear chemistry , cyclic voltammetry , chromatography , nanotechnology , chemistry , composite material , organic chemistry , composite number
A highly sensitive, simple and low cost sensor for the quantification of the diclofenac has been constructed. This sensor consists of a carbon paste nano‐structured by Multi‐Walled Carbon Nanotubes (G‐MWCNT)‐CPE. Scanning electron microscopy (SEM) and voltammetry technique were used to characterize the electrode material and to determine the analytical performances of the sensor in comparison with those obtained at a G‐CPE. The electrochemical oxidation of diclofenac on both G‐CPE and (G‐MWCNT)‐CPE electrodes is mainly controlled by adsorption, presenting a maximum peak current intensity in H 2 SO 4 0.5 mol L −1 . The carbon nanotubes, as well as they provide higher conductivity of the paste, act as spacers between the flake graphite particles and avoid their stacking in order to make the surface of graphite particles more accessible to DCF adsorption. The voltammetric measurements of diclofenac on (G‐MWCNT)‐CPE provide a large quantification range from 0.02 to 1 μmol L −1 , a detection limit of 0.004 μmol L −1 and quantification limit of 0.014 μmol L −1 under the optimized operating conditions (H 2 SO 4 , 0.25 M+KCl 0.25 M, scan rate of 30 mV s −1 , preconcentration time 18 min. and MWNTC% (30 %)). The (G‐MWCNT)‐CPE sensor was successfully applied to natural water samples, just acidified with sulfuric acid (pH<1). These samples were doped with diclofenac in sub‐micromolar range and the developed method was validated with excellent recoveries (within a maximum of 3 % difference from 100 %) for all samples indicating no interference effects of the water matrix.