Sensing Application Of Low-dimensional Carbon Materials

The electrochemical sensor is simple in preparation,low in cost,and can be detected in the field.Low dimensional carbon nano materials are widely used in the construction of electrochemical sensors because of their good conductivity and catalysis.In this paper,graphene,MOFs derived carbon materials and other low-dimensional carbon nano materials were used to prepare three electrochemical sensors,which realized the high-efficiency electrochemical detection of phenacetin,4-nitrophenol and other organic small molecules.The details are as follows:1.The reduced graphene oxide was prepared by electrochemical method and used for the detection of phenacetin for the first time.SEM test of the electrochemical reduction of graphene oxide shows that the surface of the electrochemical reduction of graphene oxide is rich in wrinkles,which has a high surface area and provides a large number of active sites for the electrochemical reaction.In the electrochemical test,the material showed higher current response and lower over potential to phenacetin.The quantitative detection of phenacetin was realized in the concentration range of 10-100 ?M,and the detection limit was 0.11 ?M.Through the study of the redox mechanism of phenacetin,we found that phenacetin produced an intermediate of quinone imine cation through oxidation reaction,and n-acetyl-p-benzoquinone imine(NAPQI)through hydrolysis.After reversible redox reaction,the mutual conversion of NAPQI and paracetamol was realized.When phenacetin and paracetamol were detected at the same time,it was found that paracetamol would not interfere with the detection of phenacetin,but the paracetamol produced by the oxidation-reduction reaction of phenacetin would affect the determination of the original paracetamol in the solution.2.The gold platinum rhodium modified MOFs derived carbon material(Au/Pt Rh-CN)was prepared by two-step method,which has good catalytic activity,interference resistance and reproducibility for the electrochemical reaction of 4-nitrophenol.In the electrochemical test,it was found that 4-nitrophenol had an obvious current response on the gold platinum rhodium alloy,and there was no characteristic peak.When Au/Pt Rh-CN is used for detection,a clear reduction peak of 4-nitrophenol can be observed,indicating that it can selectively detect 4-nitrophenol.The detection limit of 4-nitrophenol was 0.058 ?M in the range of 1-100 ?M.The mechanism of the redox reaction is that 4-nitrophenol can be reduced to 4-hydroxyaminophenol,and the conversion of 4-hydroxyaminophenol and 4-nitrosophenol can be realized by reversible redox reaction.3.The electrochemically reduced graphene oxide/ polythionine(ERGO/PTh)material was prepared by two-step method with the good stability and redox activity of polythionine and the high surface area and conductivity of electrochemically reduced graphene oxide.It showed good catalytic activity in the electrochemical detection of 4-nitrophenol.The electrochemically reduced graphene oxide has a high current response to polythionine.After polymerization,the signal of polythionine obtained in the blank solution is relatively stable,which can be used as the internal reference signal for electrochemical detection.In the range of 10-100 ?M,the ratio of 4-nitrophenol to polythionine was calculated,and the detection limit of ratio t ype was 0.0614 ?M.The detection limit of 4-nitrophenol by direct detection is 0.0367 ?M,which indicates that ratio detection is feasible.The mechanism of redox reaction on ERGO/PTh is that 4-nitrophenol generates 4-hydroxyaminophenol through reduction reaction,and the conversion with 4-nitrophenol is realized through reversible redox reaction.