Examinando por Materia "Cadmium"
Mostrando1 - 2 de 2
Resultados por página
Opciones de clasificación
- PublicaciónSólo datosIn situ-Mercury Film Electrode for Simultaneous Determination of Lead and Cadmium Using Nafion Coated New Coumarin Schiff Base as Chelating-Adsorbent(International Journal of Electrochemical Sciences, 2016-11-10) Nuñez-Dallos, Nelson; Cuadrado, Carol; Hurtado, John; Nagles, Edgar; García-Beltrán, OlimpoReaction of o-phenylenediamine and 8-formyl-7-hydroxycoumarin yield a new coumarin salen ligand, (CSB) which was isolated as orange air-stable solid and characterized by melting point, thermogravimetric analysis (TGA), mass spectra, infrared and NMR (1H, 13C) spectroscopy. New CSB was dispersed in nafion and nafion-CSB composite was deposited on a glassy carbon electrode. The modified electrode nafion-CSB/GCE allowed the formation in-situ of mercury film for detection of Pb (II) and Cd(II) by anodic stripping voltammetry (ASV) in buffer phosphate solution pH 3.0 and 4.0. Optimal conditions were studied (mercury concentration: CHg 40.0 mg L-1 ; CSB concentración; CCSB; 20.0 µmol L-1 ; pH 3.0 and pH 4.0; EACC:-1.1 V and tACC: 80).The detection limit (3σ/b) for Pb (II) Cd (II) were of 0.15 µg L–1 for Pb(II) and Cd(II) at pH 3.0. Moreover, 0.071 and 0.080 µg L–1 for Pb(II) and Cd(II), respectively at pH 4.0, The method was validated using ICP multi-element standard solution IX (Merck) containing As, Be, Cd, Cr(VI), Hg, Ni, Pb, Se and Tl 100 mg L-1 . Finally, river, tap and mineral waters were analyzed.
- PublicaciónSólo datosSimultaneous Determination of Lead and Cadmium by Stripping Voltammetry Using in-situ Mercury Film Glassy Carbon Electrode Coated with Nafion-Macrocyclic Ester(International Journal of Electrochemical Sciences, 2017-07-12) Lara, Jesid; Torres, Juan F.; García-Beltrán, Olimpo; Nagles, Edgar; Hurtado, JohnThis work report a sensitive and selective anodic stripping method for the simultaneous determination of Pb(II) and Cd(II) using (3,10,18,25-tetraoxapentacyclo [25.3.1.112,16.04,9.0 19,24] dotriaconta1(31),4(9),5,7,12(32),13,15,19,21,23,27,29-dodecaene-2,11,17,26-tetrone) macrocyclic ester (L). Anodic peak currents were increased from 1.16 to 31.48 µA for Pb(II) and 0.22 to 6.68 µA for Cd(II) when the in-situ mercury film electrode was modified with nafion and (L). Moreover, potentials separation values for Cd-Pb shift from 150 to 190 mV. Optimal parameters such as: pH; L concentration (CL), mercury concentration (CHg), accumulation potential (EACC) and accumulation time (tACC) were pH 4.0 for Pb(II) and 5.0 for Cd(II) using phosphate buffer solution (PBS), CL 12.0 mmol L -1 , CHg 28.0 mg L-1 , EACC -1.0 V and tACC 60. Detection limits (DoL) were 0.085 and 0.80 µg L-1 for Pb(II) and Cd(II) respectively. The relative standard deviation (RSD) for seven measurements of Pb(II) and Cd(II) 9.0 µg L-1 were of 2.5 and 2.0% respectively. The method was validated by ICP multielement standard solution IX (Merck) containing As, Be, Cd, Cr(VI), Hg, Ni, Pb, Se and Tl 100 mg L1 . Finally, useful of the modified electrode was developed in the analysis of Pb(II) and Cd(II) using tap water samples