以聚(3-己基噻吩)-石墨烯-Nafion修饰的玻碳电极为工作电极示差脉冲伏安法测定细颗粒物PM_(2.5)中铅的含量

DPV Determination of Pb in Fine Particles PM_(2.5) with Poly(3-Hexylthiophene)-Graphene-Nafion Modified GCE as Working Electrode

将聚(3-己基噻吩)-石墨烯在二甲基甲酰胺中的悬浮液(1g·L^(-1))10μL涂覆在玻碳电极(GCE)上,在室温干燥后,再将0.5%(质量分数)Nafion乙醇溶液滴涂于其表面,制得聚(3-己基噻吩)-石墨烯-Nafion修饰玻碳电极。用循环伏安法和示差脉冲伏安法研究了铅(Ⅱ)离子在此修饰电极上的电化学行为。结果表明:此电极对铅(Ⅱ)离子在-0.713V处出现明显的氧化峰,其峰电流为玻碳电极上的6倍。在pH 5.0的乙酸盐缓冲溶液中,在沉积电位为^(-1).0V,沉积时间为150s和扫描速率为100mV·s^(-1)的条件下,铅(Ⅱ)离子浓度在0.010~4.5μmol·L^(-1)内与其相应氧化峰电流值之间呈线性关系,检出限(3S/N)为5.0×10-9 mol·L^(-1)。在此条件下测定铅具有很好的选择性。方法用于测定环境监测站所取的PM_(2.5)实际样品,所得测定值与分光光度法测定值相符。

A portion of suspension of poly（3-hexylthiophene）-graphene（P3 HT-Gr）in DMF（1 g·L^-1,10μL）was coated onto the glassy carbon electrode（GCE）,which,after drying at room temperature,was further coated upon its surface by dropping with a definite amount of 0.5%（w）Nafion ethanol solution,thus to prepare the P3 HT-Gr-Narion modified GCE.The electrochemical behavior of Pb（Ⅱ）-ion at this modified electrode was studied by CV and DPV.It was found that an apparent oxidation peak was observed at-0.713 V,with its peak current 6 times higher than that with the bare GCE.In an acetate buffer solution of pH 5.0,and under the conditions of（1）deposition potential of^-1.0 V,（2） deposition time of 150 sand（3）scanning rate of 100 mV·s^-1,linear relationship between values of oxidation peak current and concentration of Pb2＋-ion was obtained in the range of 0.010 to4.5μmol·L^-1,with detection limit（3 S/N）of 5.0×10-9 mol·L^-1.It was shown that good selectivity was obtained in the determination of lead.The results of Pb（Ⅱ）determined in the PM（2.5） samples by the proposed method were found in consistency with those found by spectrophotometry.