Review
Electrocatalytic reduction of nitrite and bromate and their highly sensitive determination on carbon paste electrode modified with new copper Schiff base complex

https://doi.org/10.1016/j.jelechem.2017.04.046Get rights and content

Highlights

  • A modified carbon paste electrode by new synthesized Cu-complex.

  • This ME has good electrocatalytic activity towards the reduction of NO2 and BrO3.

  • High sensitivity and low LOD have been reached using DPV and amperometry.

  • Detection limits reached are 1.5 and 5.0 nM for NO2 and BrO3 respectively.

Abstract

A modified carbon paste electrode by CuII-(N,N′-bis(2,5-dihydroxybenzylidene)-1,2-diaminoethane) (CuII-DHB) as a new synthesized copper Schiff base complex. This modified electrode (ME) was constructed for the simultaneous determination of nitrite and bromate using amperometry and differential pulse voltammetry (DPV). The electrochemical characterization and electro-catalyst of NO2 and BrO3 were thoroughly investigated by cyclic voltammetry (CV). The treatment of the voltammetric results showed that it was a purely diffusion-controlled process involving one-electron in the rate-determining step. The mechanism for the interaction of nitrite with [CuII-DHB] Schiff base complex involving the (CuII/CuI) redox system. This new ME showed a good and efficient electro-catalytic activity towards the cathodic reduction of nitrite and bromate. The resulting DPV response indicates that [CuII-DHB]-CPE can be advantageously used to determine nitrite concentration in a linear range of 2–14 nM (R2 = 0.992) with a detection limit of 1.5 nM. The amperometric result reveals that [CuII-DHB]-CPE is also an effective material for bromate detection with a detection limit of 10 nM.

Introduction

The development and application of electrochemical sensors have received considerable attention in the past few years. A type of electrochemical sensors is the chemically modified electrodes (CMEs) which are most widely used to avoid the problems of poor sensitivity and selectivity faced at bare electrodes by the development of new materials, they are characterized by purposefully altering their surface characteristics to display new qualities that can be exploited for analytical purposes. The huge success of CMEs arises most often from the striking and sometimes unique properties of the modifiers [1], [2], [3]. Among these electrodes, carbon paste electrodes (CPEs), advocating a great advantages such as the easy way of built from inexpensive materials, easy renewability of the surface, wide potential window and compatibility with various types of modifiers, which have been widely used as a suitable matrices to build new modified electrodes [4], [5], [6].

The incorporation of the electroactive materials into a carbon paste electrode is advantageously applied in the electro-analytical field [7], [8].

Many researchers have given uncommon deliberation to design and synthesis of electron mediators fabricated from transition metal complexes such as those coordinated with Schiff bases, due to their preparative accessibility and structural flexibility, they exhibited stupendous biological notification including antimicrobial, anticancer and herbicidal activities [9], [10], [11].

Recently, numerous reports have been done to study the electrochemical activity and the electrocatalytic behaviors of copper Schiff base complexes. Several groups of researchers have studied the electrocatalytic behavior of copper Schiff base complex with pyrrole ring [12], and bipyridine [13]. Furthermore, in a reported study; Chen has studied the electrocatalytic reduction of NO2 using copper Schiff bases complexes (CuII) derived from the condensation of several reagents to obtain different ligands. This study has been showed that NO2 is successfully reduced to NO and then further reduction to N2O in acidic aqueous solution involving one electron reduction of Cu (II)/Cu (I) [14].

The aim of this work is to investigate the electrocatalytic activity of the new copper Schiff base complex. As shown in Fig. 1, the reaction of 2,5-dihydroxybenzaldehyde with 1,2-diaminoethane yielding the expected Schiff base ligand (HL). When this ligand is coordinated with cooper ions, it supplies strong nitrogen donor atoms. So, it can change the coordination mode of the central metal ions and the configuration of the complex. The electrode is modified by introducing the Schiff base into the matrix of paste electrode. The obtained Cu (II) complex may exhibit a configuration with μ-OAcas apical base mode. The present electrode is an easy and inexpensive way for determination of nitrite and bromate.

Section snippets

Reagents and apparatus

1,2-Diaminoethane and 2,5-dihydroxybenzaldehyde were supplied by Aldrich Chemical Co. The copper acetate Cu (OAc)2, 4H2O and absolute ethanol were obtained from Prolabo. N, N′-bis(2,5-dihydroxybenzylidene)-1,2-diaminoethane (H2DHB) was prepared as described in the literature [15]. Carbon paste electrodes (CPEs) were prepared using graphite powder < 0.1 mm obtained from Fluka. Buffer solutions (0.1 M) were prepared from sulfuric acid (H2SO4), phosphoric acid (H3PO4), and di-sodium hydrogen

Study of pH effect

The modifier [Cu-DHB)]2 + is insoluble in acidic medium but, it presents a high solubility in an alkaline medium. Therefore, the pH effect on the electrochemical behavior of the [CuII-DHB]-CPE electrode was carried out by cyclic voltammetry at 50 mVs 1 in the range of pH 1 to 6 (Fig. 2).

The peak of redox couples Cu (II)/Cu (I) is related to pH values, this latter is disappeared when the pH value > 3. On the other hand, observing the appearance of the second copper reduction peak at about pH = 1. At

Conclusion

A simple, fast and a direct prepared modified carbon paste electrode with a copper Schiff base complex as electron transfer mediator (CuII/CuI) in the carbon paste matrix was developed. The [CuII-DHB]-CPE showed a stable and reproducible electrochemical behavior, long stability, high electron transfer rate constant and excellent electrochemical reversibility. The Cu(II)/Cu(I) redox couple can be used in electrocatalysis as electron transfer mediator to shuttle electrons between analyte and the

References (27)

  • Y. Oztekin et al.

    Talanta

    (2011)
  • M. Ghiaci et al.

    Sens. Actuators B

    (2009)
  • A. Afkhami et al.

    Electrochim. Acta

    (2012)
  • A. Ourari et al.

    Electrochim. Acta

    (2015)
  • A. Ourari et al.

    Inorg. Chem. Commun.

    (2013)
  • S.M. Chen

    J. Electroanal. Chem.

    (1998)
  • M. Revenga-Parra et al.

    Sens. Actuators B

    (2005)
  • A. Salimi et al.

    Electrochem. Commun.

    (2006)
  • B.R. Limoges et al.

    Electrochim. Acta

    (2005)
  • R. Ojani et al.

    Electrochim. Acta

    (2006)
  • R. Ojani et al.

    Appl. Surf. Sci.

    (2013)
  • M.K. Ahmad et al.

    Biochimie

    (2012)
  • E. Shams et al.

    Electroanalysis

    (2006)
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