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Journal of Tea Science ›› 2011, Vol. 31 ›› Issue (6): 485-492.doi: 10.13305/j.cnki.jts.2011.06.002

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Multi-walled Carbon Nanotubes-Ionic Liquid Modified Screen-printed Carbon Electrodes for the Determination of Trace Lead in Tea

XU Xu-ming, DOU Wen-chao, ZHAO Guang-ying*   

  1. Food safety lab of Zhejiang Province, College of Food Science and Biotechnology Engineering, Zhejiang Gongshang University, Hangzhou 310035, China
  • Received:2011-03-14 Revised:2011-07-18 Online:2011-12-15 Published:2019-09-09

Abstract: A new, high sensitivity and selectivity electrochemical sensor for determination of trace lead in tea by differential pulse stripping voltammetry was investigated. For modification of the screen-printed carbon electrode, 1-butyl-3-methylimidazolium hexafluorophosphate was applied as a super conductive binder and multi-walled carbon nanotubes were used after being functionalized. They improved the conductivity and signal transduction of electrode surface. In pH4.5 NaAc-HAc buffer containing 0.006mol/L I¯, Pb2+ adsorbed onto the surface of MWCNTs-IL film coated SPCE at the deposition potential of –1.1V. During the positive potential sweep, lead was oxidized, and a good stripping peak appeared at –0.30V. Low concentration of I¯ significantly enhanced the stripping peak current of lead. The liner relationship between stripping peak value and concentration of Pb2+ was in the range of 2~600μg/L with the R value of 0.99926 and detection limit of 0.63μg/L. No significant difference existed after the detection results were compared with ICP-MS method using t test. The high sensitivity and stability of this method demonstrated the application for a simple and economical determination of trace lead in tea.

Key words: multi-walled carbon nanotubes, ionic liquid, screen-printed carbon electrode, tea, lead

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