title: Electrochemical sensors using modified electrodes based on copper complexes formed with Algerian humic acid modified with ethylenediamine or triethylenetetramine for determination of nitrite in water.
abstract: The response and efficiency of new sensors for nitrite ions analysis have been studied electrochemically. These sensors were developed by modifying a carbon paste electrode (CPE) with copper (II) complexes formed with commercial (PFHA) and Algerian (YHA) humic acids and their modified compounds with ethylenediamine (EDA) or triethylenetetramine (TETA). The developed mechanism is based on the electrochemical oxidation of NO2(-) on the modified CPE for different nitrite concentrations. The obtained results showed that the carbon paste electrode modified with copper (II)-modified humic acids complexes (Cu-MHA) exhibited substantial electrocatalytic effect on the oxidation of nitrite anions compared with carbon paste electrode. The sensitivity of the modified CPE towards nitrite concentrations depends on the nature of the humic acid and its modified compounds. The measurements performed by using CPE/Cu-YHA-EDA and CPE/Cu-YHA-TETA gave the best sensitivity and a good linear response of current versus nitrite concentrations. The oxidation peak current of nitrite at CPE/Cu-YHA-TETA and CPE/Cu-YHA-EDA electrodes in weak acid solution is proportional to the concentration of nitrite over the range 0-1.38 × 10(-2) mol L(-1) with a limit of detection (LOD) of 1.46 μmol L(-1) (Sensitivity=41.06 μA(mmol L(-1))(-1) and 2.17 μmol L(-1) (Sensitivity=27.63μA(mmol L(-1))(-1), respectively. Compared to the sensors published in the literature, our CPE/Cu-YHA-TETA and CPE/Cu-YHA-EDA electrodes exhibit a good catalytic activity towards nitrite oxidation and a low limit of detection over a wide nitrite concentrations range.
authors.affiliation: Scientific and Technical Research Center in Physical and Chemical Analysis, (CRAPC), Algiers 16004, Algeria; Laboratory of Hydrometallurgy and Molecular Inorganic Chemistry, Faculty of Chemistry, University of Sciences and Technology Houari Boumediene (USTHB), Algiers 16111, Algeria.
authors.forename: Chafia
authors.initials: C
authors.lastname: Ait Ramdane-Terbouche
authors.affiliation: Scientific and Technical Research Center in Physical and Chemical Analysis, (CRAPC), Algiers 16004, Algeria; Laboratory of Hydrometallurgy and Molecular Inorganic Chemistry, Faculty of Chemistry, University of Sciences and Technology Houari Boumediene (USTHB), Algiers 16111, Algeria.
authors.forename: Achour
authors.initials: A
authors.lastname: Terbouche
authors.affiliation: Laboratory of Hydrometallurgy and Molecular Inorganic Chemistry, Faculty of Chemistry, University of Sciences and Technology Houari Boumediene (USTHB), Algiers 16111, Algeria. Electronic address: safia.djebbar@netcourrier.com.
authors.forename: Safia
authors.initials: S
authors.lastname: Djebbar
authors.affiliation: Sciences Chimiques de Rennes, UMR CNRS 6226, Ecole Nationale Supérieure de Chimie de Rennes, Avenue du général Leclerc, CS 50837, 35708 Rennes Cedex 7, France; Université Européenne de Bretagne, 12 Avenue Janvier, 35000 Rennes, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Hauchard
keywords: Copper complexes; Detection of nitrite; Electrochemical sensors; Modified Algerian humic acid