Simple, Direct and Simultaneous Stripping Voltammetric Determination of Lead and Copper in Gasoline Using an In Situ Mercury Film Electrode
Lorena C. Martiniano, Joseany de M.S. Almeida, Glene H.R. Cavalcante, Edmar P. Marques, Teresa C.O. Fonseca, Leonardo L. Paim, Antonio G. Souza, Nelson R. Stradiotto, Ricardo Q. Aucelio and Aldalea L.B. Marques
Affiliation: Department of Chemical Technology, LPQA/LAPQAP-UFMA, São Luis, MA, Brazil.
Keywords: Simultaneous determination, lead and copper, gasoline microemulsion, anodic stripping voltammetry.
An improved procedure is presented to determine Pb(II) and Cu(II) in gasoline using a mercury film electrode
generated in situ. The method is based on the reduction of the metal ions at adequate potentials on the glassy carbon electrode,
in whose optimized microemulsion medium composition, the ions can be determined directly and simultaneously
by differential pulse anodic stripping voltammetry. Good results were obtained in terms of analytical performance and
voltammetric wave forms, with two stripping peaks near to -0.420 V and -0.13 V, attributed to Pb(II) and Cu(II), respectively.
Linear responses for both metal ions indicated quite low detection limits (2.1x 10-9 mol L-1 for Pb(II) and 2.4 x 10-9
mol L-1 for Cu(II)). The method was applied successfully to real gasoline samples, presenting good results for precision
(variation coefficients of 12.4% and 10.2%) and accuracy (recoveries ranging from 96.7 to 99.33% and 101.33 to
102.67%), for Pb(II) and Cu(II), respectively.
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