Synthesis of MnCo2O4 nanoparticles as modifiers for simultaneous determination of Pb(II) and Cd(II)

Vesna Antunović,Dijana Jelić,Aleksandar Lolić,Marija Ilić,Rada Baošić,Yogendra Kumar Mishra

doi:10.1371/journal.pone.0210904

Abstract

The porous spinel oxide nanoparticles, MnCo2O4, were synthesized by citrate gel combustion technique. Morphology, crystallinity and Co/Mn content of modified electrode was characterized and determined by Fourier transform infra-red spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction pattern analysis (XRD), simultaneous thermogravimetry and differential thermal analysis (TG/DTA). Nanoparticles were used for modification of glassy carbon electrode (GCE) and new sensor was applied for simultaneous determination of Pb(II) and Cd(II) ions in water samples with the linear sweep anodic stripping voltammetry (LSASV).The factors such as pH, deposition potential and deposition time are optimized. Under optimal conditions the wide linear concentration range from 0.05 to 40 μmol/dm3was obtained for Pb(II), with limit of detection (LOD) of 8.06 nmol/dm3 and two linear concentration ranges were obtained for Cd(II), from 0.05 to 1.6 μmol/dm3 and from 1.6 to 40 μmol/dm3, with calculated LOD of 7.02 nmol/dm3. The selectivity of the new sensor was investigated in the presence of interfering ions. The sensor is stable and it gave reproducible results. The new sensor was succesfully applied on determination of heavy metals in natural waters.

Highlights

Spinel structures with general formula AB2O4 are well known materials in the field of catalysis, especially in the area of neutralizing the harmful components from environment, such as heavy metals [1,2]
Heavy metal content is often quantified by well-known analytical methods, such as atomic absorption spectrometry (AAS) [3,4] inductively coupled plasma-mass spectrometry (ICP-MS) [5,6], inductively coupled plasma-optical emission spectrometry (ICP-OES) [7,8]and X-ray fluorescence spectrometry (XRF) [9]
Fourier transform infra-red spectroscopy (FT-IR) spectrum was observed in the range of 4000–400 cm-1 (Fig 1) which is usual for ion vibrations in the crystal lattice

Summary

Introduction

Spinel structures with general formula AB2O4 are well known materials in the field of catalysis, especially in the area of neutralizing the harmful components from environment, such as heavy metals [1,2]. Nanoparticle modifiers for heavy metal determination and transferability [10,11,12]. Numerous papers reported electrode modification such as Cu-CeO2 coated with multiwall carbon nanotubes for determination of guanine and adenine [13] or Fe3O4/RGO nanoparticles for glassy carbon electrode modification for detection of Cd(II) ions [14]. Determination of various ions such as Zn(II), Cd(II), Pb(II), Cu(II) and Ag(I) using electrode modified with chromium oxide were reported [11].ZnO are often used as sensing devices in chemical, pharmaceutical and/or agricultural applications [15,16], the group of authors investigated the application of graphene nanoparticles on environmental pollutants and detection of Al(III) ions [17,18]

Methods

Results

Conclusion