Differential pulse anodic stripping voltammetric determination of lead(II)with a 1,4-bis(prop-2 '-enyloxy)-9,10-anthraquinone modified carbon paste electrode

A sensitive and selective method for the determination of lead(II) with a 1 ,4-bis(prop-2 ' -enyloxy)-9,10-anthraquinone (AQ) modified carbon paste ele ctrode has been developed. The method is based on non-electrolytic preconce ntration via complex formation with modifier, followed by an accumulation p eriod with a negative potential ( -1.5 V), and then by a proper anodic stri pping. The analytical performance was evaluated with respect to the quantit y of modifier in the paste, concentration of electrolyte solution, preconce ntration time, lead(II) concentration, and other variables. A linear calibr ation graph was obtained in the concentration range 2.00 x 10(-9)-1.06 x 10 (-5) M Pb(II) (n = 21, r = 0.9999) with 30 s preconcentration time. The det ection limit was found to be 1 x 10(-9) M. For eight preconcentration/deter mination cycles, the differential pulse voltammetric response was reproduce d with 5.0 and 3.7% relative standard deviations at 2.00 x 10(-8) and 2.00 x 10(-6) M Pb(II), respectively. Rapid and convenient renewal of electrode surface allows the use of a single modified electrode surface in multiple a nalytical determinations over several weeks. Many coexisting metal ions had little or no effect on the determination of lead(II). The developed method was applied to lead determination in waste waters. (C) 2001 Elsevier Scien ce B.V. All rights reserved.