Electrochemical Sensor Based On Nanocomposites For Detection Of Tryptophan And Heavy Metal Ions

Poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid(PEDOT:PSS)is a promising new conductive polymer,which has attracted the attention of researchers in many fields due to its high conductivity,good stability and film-forming,excellent biocompatibility and thermal mechanical properties.As a common carbon material,reduced graphene oxide(rGO)has significant advantages such as large specific surface area,high stability,high mechanical strength and good chemical activity,so it can be used as modified material of electrochemical sensor.Sodium Carboxymethyl Cellulose(CMC)not only combines the materials well,but also enhances the bonding between the materials and the electrode.In the first work,PEDOT:PSS,rGO and CMC are combined to form PEDOT:PSS/rGO/CMC nanocomposite film,which is used as modified material to construct PEDOT:PSS/rGO/CMC/GCE electrochemical sensor.The detection result of tryptophan under optimal experimental conditions has a good linear range of 3 ?mol/L to 1500 ?mol/L and a detection limit of 0.1?mol/L.In addition,the next experiment demonstrates that PEDOT:PSS/rGO/CMC/GCE has excellent stability and repeatability.More importantly,the specificity and anti-interference of the sensor for tryptophan are excellent.Among the 14 amino acids,the sensor only has electrochemical response to tryptophan,and in the presence of the other 13 amino acids,the result is almost unchanged with only tryptophan.This excellent specificity and anti-interference can be of great significance in actual detection.In order to study the performance of the proposed sensor in act ual samples,quantitative tryptophan is placed in the milk sample,and the detection result is in the linear relationship.The PEDOT:PSS/rGO/CMC/GCE sensor realizes the detection of tryptophan,which provides a new research idea for food safety determination.The next work is an electrochemical sensor based on a novel carbon nanomaterial of nitrogen-doped graphene(NGO)for the simultaneous detection of Zn(?),Cd(?),Sn(?)and Pb(?).The presence of NGO enhances the electrochemical activity,and the results show that the NGO/GCE with prominent electrochemical performance is superior to the other electrodes for the detection of Zn(?),Cd(?),Sn(?)and Pb(?).The SWASV method is used in the subsequent electrochemical detection.The experimental results show that the electrochemical sensor has a good linear detection range and a low detection limit for simultaneous detection of the above four heavy metal ions,and the linear range of Zn(?)is 2-12 ?mol/L,the detection limit is 0.1 ?mol/L;the linear range of Cd(?)is 1.5-7?mol/L,the detection limit is 0.01 ?mol/L;the linear range of Sn(?)is 2-12 ?mol/L,the detection limit is 0.02 ?mol/L;the linear range of Pb(?)is 1-6?mol/L,and the detection limit is 0.01?mol/L.In addition,in order to prove the feasibility of the sensor in the actual water samples,the water samples obtained from three different water sources are actually tested,and the expected results are obtained.The electrochemical sensor exhibits excellent sensitivity and obvious discrimination in the detection of Zn(?),Cd(?),Sn(?)and Pb(?),which provides a new research idea for the monitoring of heavy metal ion water pollution.