An Electrochemical Sensing Method Based On Graphene- Polypyrrole For Detection Of Lead Ion

Pb2+has been recognized as a representative pollutant. It is hazardous and hard to be degraded in the environment. Moreover, it could be accumulated through biologic chain and threaten human health. Thus it is essential to monitor and control the content of Pb2+ in the environmental water system. There have been some analytical methods for detecting Pb2+, such as:inductively coupled plasma/atomic emission spectrometry (ICP/AES), atomic absorption spectroscopy (AAS) and so on. However, some critical issues are still to be addressed, for instance:time-consuming in sample pretreatment, highly expensive and complex instruments, low sensitivity and so forth. Therefore, it is essential to develop an analysis method for rapid, selective and detection of trace Pb2+.Here, we developed an electrochemical sensing method for selective and sensitive detection of Pb2+. This method had good practicality and the synthesis method of sensing material was quite simple. In the present study, we fabricated polypyrrole-graphene (PPY-rGO) nanocomposite facilely by electrochemical polymerization. The unique 3D porous PPY-rGO nanocomposite was successfully prepared and displayed excellent performance such as great electric conductivity, stable chemical physical properties and environment-friendliness. Polypyrrole was served as lead ion probe. Combining excellent electrical conductivity and larger electroactive area of graphene, we established an electrochemical sensor based on PPY-rGO nanocomposite for selective and sensitive detection of Pb2+. The electrochemical response of this method is quite good, and the electrochemical properties and performance of nanocomposite were validated by material characterization and actual test. Under optimum conditions, the electrochemical response of this method was over concentration range of 5×10-9 to 7.5×10-7 mol/L, with limit of 4.7×10-11 mol/L (3a method). In addition, no obvious responses were noticed for other interfering metal ions such as Cu2+, Hg2+, Zn2+, Cd2+ during interference test, which proved the good specificity of this sensor. It could be applied in practical determination of Pb2+.This research utilized selective recognition of the polypyrrole and conductive performance of graphene, designing an electrochemical method for rapid, sample and sensitive detection of Pb2+. It could also provide a reference for the sensing application of recombination between conducting polymers and carbon nanometer material.