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

Abstract

Owing to large specifi c surface area, good conductivity, and high adsorption power [1], carbon nanotubes (CNT) are widely used today as modifi ers of the surface of indicator electrodes for voltammetry. The simplicity of voltammetric measurements, low detection limits of elements being determined, short analysis time, reliability, and small size and low cost of the equipment allow stripping voltammetry (SV) to compete with other highsensitivity methods (e.g., atomic absorption spectroscopy, mass spectrometry, chromatography, etc.) in analysis of water, soil, foodstuffs, and various biological materials for the determination of heavy metal traces [2].The use of CNT for enhancing the sensitivity of glassy carbon, carbon paste, and impregnated electrodes to metal ions in methods of anodic [3-9], cathodic [10], and adsorptive stripping voltammetry (AdSV) [11][12][13][14][15][16][17] has been reported. However, these solid-phase sensors are expensive and require manual mechanical treatment of the surface between the measurements, so that the analysis results become fully dependent on the analyst skill.On the other hand, thick-fi lm technologies of screen printing are a simple, quick, and cheap method for mass-scale production of disposable electrochemical sensors characterized by high accuracy and wide spec-Abstract-Multi walled carbon nanotubes were used for modifi cation of thick-fi lm carbon-containing electrodes for adsorptive stripping voltammetry. A complex compound of Fe(III) with pyrocatechol was chosen as model system. As compared to the electrodes fabricated without using carbon nanotubes, the modifi ed ones have the recovery close to 100%, 2 times higher sensitivity, and 3 times lower limit of detection. The developed sensors can be used for quick determination of trace amounts of iron in real objects.