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Optimizing the differential pulse anodic stripping voltammetry method with hanging mercury electrode for thallium (I) determination in the presence of lead (II) and copper (II) for application in contaminated soils

dc.contributor.authorCruz Hernández, Yusniel
dc.contributor.authorVillalobos, Mario
dc.contributor.authorGonzález Chavez, José Luz
dc.contributor.authorMartínez Villegas, Nadia Valentina
dc.date.accessioned2020-03-25T01:26:40Z
dc.date.available2020-03-25T01:26:40Z
dc.date.issued2019
dc.identifier.citationCruz-Hernández, Y., Villalobos, M., González-Chavez, J., & Martínez-Villegas, N. (2019). Optimizing the differential pulse anodic stripping voltammetry method with hanging mercury electrode for thallium (I) determination in the presence of lead (II) and copper (II) for application in contaminated soils. Revista Internacional de Contaminación Ambiental, 35(2), 481-494. doi:http://dx.doi.org/10.20937/RICA.2019.35.02.18
dc.identifier.urihttp://hdl.handle.net/11627/5335
dc.description.abstract"The conditions that allow thallium (I) determination in the presence of lead (II) and copper (II) were optimized without prior separation of these cations, using a previously developed differential pulse anodic stripping voltammetry (DPASV) method, with a hanging mercury drop working electrode (HMDE) and a Ag/AgCl reference electrode. Unfortunately, the electrochemical activity of lead (II) interferes with this determination, but the addition of 0.1 M EDTA complexing agent (at pH = 4.6) causes a shift in the Pb(II) peak to more negative values, making it possible to quantify Tl(I) in its presence at an optimal deposition potential of -0.550 V. However, the Cu(II) reduction peak, which is normally found far away from that of Tl(I), is also shifted when complexed with EDTA, approaching the Tl(I) peak and becoming an interfering ion. The deposition time and scan rate that were found optimal for the determination were 30 s and 10 mV/s, respectively. Under these conditions it was found that maximum concentration ratios for Pb(II)/Tl(I) and Cu(II)/Tl(I) of 2000 and 400, respectively, did not show interference thus duplicating and quadruplicating the concentrations of Pb(II) and Cu(II), respectively above which interference with Tl(I) occurs, as compared to the standard method published. The proposed methodology has a detection limit of 2 mu g/L, a quantification limit of 7 mu g/L, and a linear range between 2.3 and 20 mu g/L. Enriched Tl solutions of 0.5, 2.5 and 9 mu g/L showed excellent recoveries. The methodology was applied to extractions of contaminated soil samples with Tl contents from 0.05 to 3.2 mg/kg.
dc.description.abstract"Se optimizaron las condiciones para la determinación de talio (I) en presencia de plomo (II) y cobre (II) sin separación preliminar de estos iones, a partir de un método ya establecido de voltametría de redisolución anódica diferencial de pulsos, usando un electrodo colgante de gota de mercurio y un electrodo de Ag/AgCl. Desafortunadamente, la actividad electroquímica del plomo (II) interfiere en la determinación de talio (I), pero la adición del agente complejante EDTA 0.1 M (a pH = 4.6) provoca un desplazamiento del pico del plomo (II) a valores más negativos, a un potencial de deposición óptimo de –0.550 V. Sin embargo, el pico de reducción del Cu(II) también se desplaza al complejarse con el agente EDTA, acercándose al del Tl(I) y convirtiéndose en un ion interferente. El tiempo de deposición y la velocidad de barrido que se encontraron óptimos para la determinación fueron de 30 s y 10 mV/s, respectivamente. Bajo estas condiciones se encontró que relaciones máximas de concentración Pb(II)/Tl(I) y Cu(II)/ Tl(I) de 2000 y 400, respectivamente, no interfieren, permitiendo duplicar y cuadruplicar la concentración de Pb(II) y de Cu(II), respectivamente, que no interfieren con el Tl(I) respecto al método estándar publicado. La metodología propuesta tiene un límite de detección de 2 µg/L, un límite de cuantificación de 7 µg/L y un intervalo lineal entre 2.3 y 20 µg/L. Soluciones de Tl enriquecidas con 0.5, 2.5 y 9 µg/L mostraron excelentes porcentajes de recuperación. Se aplicó la metodología en diferentes extractos de suelos contaminados cuyo contenido de Tl varió de 0.05 a 3.2 mg/kg."
dc.publisherUniversidad Nacional Autónoma de México, Universidad Autónoma de Tlaxcala, Universidad Veracruzana, Universidad Autónoma de Occidente, Centro de Ciencias de la Atmósfera
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internacional
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subjectVoltamperometric
dc.subjectInterference
dc.subjectTrace analysis
dc.subjectThallium
dc.subjectEDTA
dc.subjectSoil samples
dc.subject.classificationCIENCIAS DE LA TIERRA Y DEL ESPACIO
dc.titleOptimizing the differential pulse anodic stripping voltammetry method with hanging mercury electrode for thallium (I) determination in the presence of lead (II) and copper (II) for application in contaminated soils
dc.typearticle
dc.identifier.doihttp://dx.doi.org/10.20937/RICA.2019.35.02.18
dc.rights.accessAcceso Abierto


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Attribution-NonCommercial-NoDerivatives 4.0 Internacional
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