“…Co (II), Cr (III), Cr (VI), Fe (II) and Ni (II) ions did not significantly affect the (I 0 /I) ratio. The most accentuated interference was provided by Fe (III) and Cu (II) ions, result that we have associated to surface oxide formation, formation of intermetallic compounds, or competition toward active sites on the electrode surface [ 28 , 29 ]. Figure 5 Effect of interfering ions (200 μg·L −1 each interfering metal) in the Pb (a) and Cd (b) determination (50 μg·mL −1 in solution).…”
The evaluation of glassy carbon (GC) electrodes modified with a Nafion (Nf) film and doped with nanoalloys (Nys) deposits of Ag–Hg and Ag–Bi and their application to determination of Cd (II) and Pb(II) in marine sediments, is described. Deposited Ag–Hg and AgBi Nys have a size of approximately ~80 nm dispersed and embedded inside the booths of the Nf net, while other of them remained on Nf net surface. For the AgBiNysNf-GC electrode, a detection limit (DL), 3 s criterion, slightly higher than for the AgHgNysNf-GC modified electrode was obtained. Accuracy of measurements was asserted by comparison with quantification of Cd and Pb in three sets of marine sediments samples previously analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The values of the standard deviation and the coefficients of variation are very low, and also comparable between the different determinations.
“…Co (II), Cr (III), Cr (VI), Fe (II) and Ni (II) ions did not significantly affect the (I 0 /I) ratio. The most accentuated interference was provided by Fe (III) and Cu (II) ions, result that we have associated to surface oxide formation, formation of intermetallic compounds, or competition toward active sites on the electrode surface [ 28 , 29 ]. Figure 5 Effect of interfering ions (200 μg·L −1 each interfering metal) in the Pb (a) and Cd (b) determination (50 μg·mL −1 in solution).…”
The evaluation of glassy carbon (GC) electrodes modified with a Nafion (Nf) film and doped with nanoalloys (Nys) deposits of Ag–Hg and Ag–Bi and their application to determination of Cd (II) and Pb(II) in marine sediments, is described. Deposited Ag–Hg and AgBi Nys have a size of approximately ~80 nm dispersed and embedded inside the booths of the Nf net, while other of them remained on Nf net surface. For the AgBiNysNf-GC electrode, a detection limit (DL), 3 s criterion, slightly higher than for the AgHgNysNf-GC modified electrode was obtained. Accuracy of measurements was asserted by comparison with quantification of Cd and Pb in three sets of marine sediments samples previously analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The values of the standard deviation and the coefficients of variation are very low, and also comparable between the different determinations.
“…Sobre el cátodo de Au/Hg, la presencia de Pb entre 10-100 veces mayor a la concentración del Sb 3 + disminuyó la señal Sb en un 58% y 54% sobre el cátodo de Ag/Hg. Resultado que puede ser consecuencia de la formación de productos colaterales, tales como PbH 4 (Sáenz, 2012y Bolea, 2001) y/ó el adduto intermetálico Sb-Pb (Zmen, 2004). Sobre el cátodo Au/Hg la presencia de Cu 2+ a una concentración igual a la del Sb 3+ ,disminuyó la señal un 29% ; cuando se aumento la concentración a 10 veces la cantidad de Sb 3+ , no se observó ningún cambio en la señal.…”
Los objetivos del Foro Iberoamericano de los Recursos Marinos y la Acuicultura(FIRMA) siempre han constituido un reto para la organización en cualquier paísdonde se ha desarrollado, pero siempre un puñado de voluntades ha generadojunto con los participantes una ola académica llena de hermandad que haconllevado al éxito, el VII FIRMA Ecuador 2014, independientemente decualquier obstáculo, no ha sido la excepción, confirmando que es uno de loseventos más importantes en la Evaluación de los Recursos Marinos y laAcuicultura, y al menos único en su forma y objetivos.
“…The electrochemical generation cell has been described in detail in our previous publications [20,21]. It consists of a compartment which houses a tubular chamber made out of glass (5.5 cm 3 ) where the electrochemical reaction is held, a cathode (Au, Pt, Pb, RGC or Au/Hg) and a spiral platinum anode which completely surrounds the cathode.…”
“…Unfortunately, some of these cathodes present low mechanical stability and therefore must be periodically replaced [19].The search for a convenient cathode material for EcHG with high hydrogen over-voltage, acceptable freedom from interference and sufficient mechanical stability, is still on. Electrochemical arsine generation is well documented in the literature [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. The present work proposes a methodology for electrochemical arsine generation using a mechanically stable gold cathode whose hydrogen over-voltage is increased by means of mercury amalgamation.…”
Section: Introductionmentioning
confidence: 99%
“…This could mean that the active sites on the cathode surface are not operationally optimal for the electrochemical generation of arsine. Using the Pb cathode (PbH 4 as a competitor to arsine generation[21], could explain the reduction in absorbance. It is interesting to notice that the absorbance signal does not disappear even at 1.2 A.…”
The electrochemical generation of arsenic volatile species (arsine) using an Au/Hg amalgam cathode in a 0.5 M H 2 SO 4 solution, is described. Results were compared with those obtained with other cathodes commonly used for generation of arsine. The effects of the electrolytic conditions and interferent ions have been studied. Results show that the Au/Hg cathode has better tolerance to interference and higher repeatability than cathodes made out of platinum (Pt), gold (Au), reticulated glassy carbon (RGC), lead (Pb). Under optimized conditions, a 0.027 µg L −1 (3σ) detection limit for As (III) in aqueous solutions and a 2.4 % relative standard deviation for a 0.1 µg L −1 As (III) were obtained. The accuracy of the method was verified by determination of As in a certified reference material. The proposed method was applied to the determination of As in spiked tap water samples.
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