THE DETERMINATION OF LEAD IN TEA SAMPLES BY UPD-SWASV METHOD ON GOLD DISC ELECTRODE

ABSTRACT

Cyclic voltammetry (CV) and the square wave anodic stripping voltammetry (SWASV) were used for investigation of Pb(II) underpotential deposition (UPD) on gold disc electrode. Based on the electrochemical properties of Au/Pb UPD system, a new method of UPD-SWASV for determination lead(II) was established. A solution containing 0.01 M HNO₃ and 0.01 M NaCl was selected as the supporting electrolyte. Factors affecting the Pb(II) UPD and stripping steps were investigated and an optimized analytical procedure was developed. The calibration plots for Pb(II) concentration in the range 5.0 × 10⁻⁹–1.0 × 10⁻⁶ M were obtained. For eight successive determinations of 5.0 × 10⁻⁸ M Pb(II), an RSD of 7.4% was found. The developed method was applied to lead determination in tea samples. The method was validated with AES.

Keywords:

• Lead
• Tea samples
• Determination
• Underpotential deposition
• Gold disc electrode
• Square wave anodic stripping voltammetry

Acknowledgments