Voltammetric Determination of the Herbicide Linuron Using a Tricresyl Phosphate-Based Carbon Paste Electrode

This paper summarises the results of voltammetric studies on the herbicide 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (Linuron), using a carbon paste electrode containing tricresyl phosphate (TCP-CPE) as liquid binder. The principal experimental conditions, such as the pH effect, investigated in Britton-Robinson buffer solutions (pH 2.0–7.0), the peak characteristics for the analyte of interest, or instrumental parameters for the differential pulse voltammetric mode were optimized for the method. As found out, the best electroanalytical performance of the TCP-CPE was achieved at pH 2.0, whereby the oxidation peak of Linuron appeared at ca. +1.3 V vs. SCE. The analytical procedure developed offers good linearity in the concentration range of 1.25–44.20 μg mL−1 (1.77 × 10−4–5.05 × 10−6 mol L−1), showing—for the first time—the applicability of the TCP-CPE for anodic oxidations in direct voltammetry (without accumulation). The method was then verified by determining Linuron in a spiked river water sample and a commercial formulation and the results obtained agreed well with those obtained by the reference HPLC/UV determination

Porous electrodes for bioanalytical applications

Dans cette mémoire nous discutons l élaboration d électrodes poreuses par un processus de type template et leur application potentielle dans le domaine de l analyse environnementale et neurobiologique. La première partie de ce travail est dédiée à l'élaboration d électrodes poreuses de bismuth et d'antimoine. Ces électrodes montrent des limites de détection améliorées par rapport à des électrodes non poreuses, ouvrant ainsi des applications prometteuses dans le domaine de l'analyse de trace. La deuxième partie vise à surmonter des facteurs limitants de micro-électrodes dans le cadre de l'enregistrement de signaux extracellulaires et la stimulation de réseaux neuronaux en culture, qui peut donner des informations sur des interactions et des phénomènes synergétiques dans les systèmes nerveux.In the present dissertation thesis the elaboration of porous electrodes via templating methods and their potential application in the field of environmental and neurobiological analysis are discussed. The electrodes of controlled porosity are characterized by an increased internal electroactive area and thus they can be used to enhance significantly the electrochemical performance. High surface area materials are promising for biosensing and more generally in electrochemical experiments. The first part of this work is focused on the elaboration of porous bismuth and antimony film electrodes. These porous electrodes show improved detection limits compared to non-porous one and thus open up promising applications in the field of trace analysis. The second part deals with overcoming limiting factors of microelectrode arrays in the context of extracellular recording and stimulating cellular neuronal networks or neural tissues in culture that can reveal information about interactions and synergetic features of nervous systems.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Electrochemical sensors and biosensors based on heterogeneous carbon materials

International audienceAn overview of the use of electrochemical sensors made from heterogeneous carbon materials (carbon paste electrodes, screen-printed carbon electrodes) in the field of food analysis is presented. Sensors for inorganic and organic analytes as well as biosensors are summarized

Enzyme-Linked Electrochemical Detection of PCR-Amplified Nucleotide Sequences Using Disposable Screen-Printed Sensors. Applications in Gene Expression Monitoring

Electrochemical enzyme-linked techniques for sequence-specific DNA sensingare presented. These techniques are based on attachment of streptavidin-alkalinephosphatase conjugate to biotin tags tethered to DNA immobilized at the surface ofdisposable screen-printed carbon electrodes (SPCE), followed by production andelectrochemical determination of an electroactive indicator, 1-naphthol. Via hybridizationof SPCE surface-confined target DNAs with end-biotinylated probes, highly specificdiscrimination between complementary and non-complementary nucleotide sequences wasachieved. The enzyme-linked DNA hybridization assay has been successfully applied inanalysis of PCR-amplified real genomic DNA sequences, as well as in monitoring of planttissue-specific gene expression. In addition, we present an alternative approach involvingsequence-specific incorporation of biotin-labeled nucleotides into DNA by primerextension. Introduction of multiple biotin tags per probe primer resulted in considerableenhancement of the signal intensity and improvement of the specificity of detection

Study of a new solid carbon paste tyrosinase-modified amperometric biosensor for the determination of catecholamines by high-performance liquid chromatography

The performance of a tyrosinase-modified 'solid carbon paste' electrode (SCPE) as electrochemical detector has been studied in comparison with a glassy carbon electrode detector in high-performance liquid chromatography for the simultaneous determination of dopamine, 3,4-dihydroxyphenylacetic acid, norepinephrine and homovanillic acid. The influence of pH, flow-rate and amount of organic solvent in the mobile phase on the biosensor response was investigated. The stability and selectivity of the detector were significantly affected by the mobile phase pH. No effect of 2% isopropanol in the mobile phase was observed. The biosensor response was fast, reproducible, highly sensitive and linear over the concentration range 0.09 μM-1 mM (detection limit of ca. 290 pg of neurotransmitter injected).info:eu-repo/semantics/publishe

Carbonaceous materials for single-use sensors. Quality assessment by electrochemical impedance spectrometry

An overview of achievements and prospects of electrochemical impedance spectrometry (EIS) application for characterizing the surface of the carbon paste electrode (CPE) is emphasized. Several guidelines are pointed out and illustrated by preliminary experimental result