MWCNTs-IL-SPCE传感器检测茶叶中痕量铅研究

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

研究构建了一种新型、高灵敏性和高选择性的电化学传感器,结合差分脉冲溶出伏安法快速检测茶叶样品中的痕量铅。采用超传导性粘结剂离子液体1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6)和功能化的多壁碳纳米管(MWCNTs)修饰丝网印刷碳电极,提高了电极表面的导电性和信号转换。在含0.006 mol/L I-,pH4.5的NaAc-HAc缓冲液中,Pb2+在-1.1 V沉积电位下吸附于MWCNTs-IL-SPCE膜上,当正电压扫过时,铅氧化溶出,在-0.30 V下出现一个很好的溶出峰,低浓度的Iˉ明显增强了铅的溶出峰电流。溶出峰高值与Pb2+浓度在2～600μg/L范围内呈线性关系,相关系数为0.99926,检测限为0.63μg/L。试验结果与ICP-MS测定值进行t检验,无显著性差异。该方法灵敏、稳定,可用于茶叶中痕量铅简单、经济的检测。

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 0.006 mol/L Iˉ,Pb2＋ adsorbed onto the surface of MWCNTs-IL film coated SPCE at the deposition potential of-1.1 V.During the positive potential sweep,lead was oxidized,and a good stripping peak appeared at-0.30 V.Low concentration of Iˉ significantly enhanced the stripping peak current of lead.The liner relationship between stripping peak value and concentration of Pb2＋ was in the range of 2～600 μg/L with the R value of 0.99926 and detection limit of 0.63 μg/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.