Determination of Lead and Cadmium in the Presence of Quercetin-5 %26apos;-sulfonic Acid by Adsorptive Stripping Voltammetry with a Hanging Mercury Drop Electrode and a Nafion-coated Mercury Film Electrode

作者：Nagles Edgar^*; Arancibia Veronica; Rios Roxana

来源：International Journal of Electrochemical Science, 2012, 7(5): 4545-4558.

• Adsorptive stripping voltammetry
• Nafion-coated mercury film electrode
• Pb(II) and Cd(II) determination
• Quercetin-5 %26apos
• -sulfonic acid
• Water analysis

The use of a hanging mercury drop electrode (HMDE) and a glassy carbon electrode modified with Nafion-Hg (NHgFE) to determine Pb(II) and Cd(II) by adsorptive stripping voltammetry in the presence of quercetin-5%26apos;-sulfonic acid (QSA) is reported. With a HMDE it is possible to determine Pb(II) and Cd(II) individually because the peak current of Pb-QSA is maximum at pH 6.1 (E-peak -0.50 V), while the peak current of the Cd-QSA complex is maximum at pH 8.9 (E-peak -0.66 V). The linear calibration curves ranged from 0.5-40.0 mu g L-1 for Pb(II) and 0.5-45.0 mu g L-1 for Cd(II). The detection limits (3 sigma) were estimated to be around 0.3 and 0.1 mu g L-1 and the relative standard deviations were 2.0 and 1.7 % at the 9.4 mu g L-1 level of Pb(II) and Cd(II) with 30 s of accumulation (n=7) (C-QSA 2.7 mu mol L-1; E-ads -0.10 V). On the other hand, it is found that with the prepared Nafion-mercury film electrode Pb(II) and Cd(II) can be analyzed simultaneously at pH 6.1 (E-peak -0.55 V, -0.73 V). The detection limits were 0.2 mu g L-1 for both metal ions, with a linear range until 18.0 mu g L-1. The methods were validated using synthetic sea water (ASTM D665) spiked with several metal ions, and reference material for measuring of elements in water (TMDA-61) and waste waters (SPS-WW1). Finally, the method was successfully applied to the determination of Pb(II) and Cd(II) in tap water after UV digestion.

• 出版日期2012-5