title: Electrochemical determination of arsenic in natural waters using carbon fiber ultra-microelectrodes modified with gold nanoparticles.
abstract: We have developed an anodic stripping voltammetry method that employs carbon fiber ultra-microelectrodes modified with gold nanoparticles to determine arsenic in natural waters. Gold nanoparticles were potentiostatically deposited on carbon fiber ultra-microelectrodes at -0.90V (vs SCE) for a time of 15s, to form the carbon fiber ultra-microelectrodes modified with gold nanoparticles. Cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy coupled to an X-ray microanalysis system were used to check and confirm the presence of gold nanoparticles on the carbon fiber ultra-microelectrodes. Arsenic detection parameters such as deposition potential and deposition time were optimized allowing a detection range between 5 to 60µgL-1. The developed modified electrodes allowed rapid As determination with improved analytical characteristics including better repeatability, higher selectivity, lower detection limit (0.9μgL-1) and higher sensitivity (0.0176nAμgL-1) as compared to the standard carbon electrodes. The analytical capability of the optimized method was demonstrated by determination of arsenic in certified reference materials (trace elements in water (NIST SRM 1643d)) and by comparison of results with those obtained by hydride generation atomic absorption spectrometry (HG-AAS) in the determination of the analyte in tap and well waters.
authors.affiliation: Hidroecuador, Apartado EC1701, Quito, Ecuador.
authors.forename: Patricio
authors.initials: P
authors.lastname: Carrera
authors.affiliation: Escuela Politécnica Nacional, Centro de Investigación y Control Ambiental, Apartado 170413, Quito, Ecuador.
authors.forename: Patricio J
authors.initials: PJ
authors.lastname: Espinoza-Montero
authors.affiliation: Universidad Simón Bolívar, Departamento de Química, Apartado 89000, Caracas, Venezuela. Electronic address: lfernandez@usb.ve.
authors.forename: Lenys
authors.initials: L
authors.lastname: Fernández
authors.affiliation: Universidad Técnica de Machala, Facultad de Ciencias Químicas y de la Salud, Apartado 070151, Machala, Ecuador.
authors.forename: Hugo
authors.initials: H
authors.lastname: Romero
authors.affiliation: Universidad Simón Bolívar, Departamento de Química, Apartado 89000, Caracas, Venezuela.
authors.forename: José
authors.initials: J
authors.lastname: Alvarado
mesh_terms: D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D000077482:Carbon Fiber; D004563:Electrochemistry / Q000295:instrumentation*; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D008839:Microelectrodes; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D000077482:Carbon Fiber; D014874:Water Pollutants, Chemical; D014867:Water; D002244:Carbon; D006046:Gold; D001151:Arsenic
keywords: Anodic stripping voltammetry; Arsenic electrochemical detection; Carbon fiber ultra-microelectrodes; Gold nanoparticles