Abstract
AbstractThe widely employed electroanalytical technique of adsorptive stripping voltammetry (AdsSV) is critically assessed and evaluated at a wide and diverse range of unmodified and nano‐particle modified carbon electrodes using the analyte fipronil as a paradigmatic case. The generic electroanalytical performances of the nano‐particle modified electrodes are investigated and compared with the unmodified electrodes revealing similar LOD values and pointing to intrinsic limitations of AdsSV arising from the non‐independence of the Faradaic and capacitive signals during the stripping step. Methods for facilitating the adsorption or using different waveforms that may offer a more favourable limit of detection (LOD) at the nano‐particle modified electrodes are suggested and assessed, specifically the use of adsorption onto particles prior to their use for modifying electrodes and also the recently introduced method of semi‐circular voltammetry.
Highlights
Stripping voltammetry is a widely adopted strategy in electroanalysis since it offers the opportunity to enhance the sensitivity of the electrochemical method and to reach lower limits of detection than those direct forms of voltammetry where the size of the analytical signal is inevitably limited by the rate of diffusion to the electrode.[2]
The methods reported for the analysis of fipronil are mostly chromatographic,[25] while recently some cheap and rapid techniques have emerged[26] including a few electrochemical methods.[26c–h] The method we evaluate in the present paper employing adsorptive stripping voltammetry (AdsSV) on the aforementioned carbon electrodes, on a carbon nanotubes (CNTs) modified surface can be seen in principle as an electroanalytical method alternative
The adsorption of FIP on single multiwalled carbon nanotubes (MWCNTs) is investigated via nano-impacts
Summary
Stripping voltammetry is a widely adopted strategy in electroanalysis since it offers the opportunity to enhance the sensitivity of the electrochemical method and to reach lower limits of detection than those direct forms of voltammetry where the size of the analytical signal is inevitably limited by the rate of diffusion to the electrode.[2]. As a model target analyte we consider the molecule fipronil (Scheme 1), a phenyl-pyrazole insecticide used for pest control on crops, household pets and domestic animals.[19] Fipronil and its metabolites display neurotoxicity[20] and potential genotoxicity[21] towards non-target animals including humans.[22] The wide use of fipronil has raised concerns because of the residual fipronil present in soil or aquatic ecosystems[20,23] given its threat to human health.[24] The methods reported for the analysis of fipronil are mostly chromatographic,[25] while recently some cheap and rapid techniques have emerged[26] including a few electrochemical methods.[26c–h] The method we evaluate in the present paper employing AdsSV on the aforementioned carbon electrodes, on a CNT modified surface can be seen in principle as an electroanalytical method alternative. The chronoamperograms were recorded for 20 s at varying potentials from 0.8–1.7 V vs SCE
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