Sensitive Voltammetric Detection of Trace Heavy Metals in Real Water Using Multi-Wall Carbon Nanotubes/Nafion Composite Film Electrode

Abstract

Multi-wall carbon nanotubes (MWCNTs) and Nafion composite film (MWCNTs/Nafion) were used for fabricating electrochemical sensors for the voltammetric detection of trace lead(II) and cadmium(II) in several water samples. The morphology and structure of MWCNTs/Nafion film were characterized by scanning electron microscopy (SEM) and infrared spectrum (IR). The electron transfer of MWCNTs/Nafion composite film was examined by cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). Various experimental parameters, which influenced the response of MWCNTs/Nafion/GC to target metals, were optimized. The results showed that the synergistic effect was obtained on the MWCNTs/Nafion/GC whose sensitivity and stability were better than those of Nafion-coated electrode (Nafion/GC) or CNTs/GC. Stability of the Pb(II) and Cd(II) stripping signals was excellent with relative standard deviations (RSD) within 5% (n＝10) from one electrode preparation to another, and RSD of 30 µg•L -1 Pb(II) and Cd(II) were 2.8% and 3.2% for 20 repeated analysis on one single CNTs/Nafion/GC.Over 50 runs, the stability of Pb and Cd detection at the MWCNTs/Nafion conposites electrode was still satisfactory with RSD lower than 6.0%. The determination limits (S/N＝3) of the proposed method were determined to be 100 ng•L -1 for Pb and 150 ng•L -1 for Cd. Finally, the MWCNTs/Nafion/GC was successfully applied to determine Pb(II) and Cd(II) in different water samples with recoveries of 97%-103% for Pb and 96%-104% for Cd.

Surface selectivity competition of newly synthesized polyarylidene(keto amine) polymers toward different metal ions

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Selective Iron(III) ion uptake using CuO-TiO2 nanostructure by inductively coupled plasma-optical emission spectrometry

“…In addition, the development of simple, rapid and efficient techniques has achieved a huge interest for monitoring metal ions in the environment. Several analytical methods have been applied to analyze metal ions in aqueous solutions, such as atomic absorption spectrometry [34], inductively coupled plasma-optical emission spectrometry (ICP-OES) [35], anodic stripping voltammetry [36], and ion chromatography [37]. However, analytical methods can not directly measures the metal ions, in particular at ultra-trace concentration, in aqueous systems due to the lack of sensitivity and selectivity of these methods.…”

Thick-film carbon-containing electrodes modified with multi-walled carbon nanotubes in adsorptive stripping voltammetry of iron(III)

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