Application Of Transition Metal Compound/Carbon Composite Modified Electrode In Electrochemical Sensing

In recent decades,with the vigorous development of social economy and the continuous improvement of people's living standards,people's growing attention to the food and drug safety,fake drugs and drug abuse poses a serious threat to people's health,Thus,precise and efficient analysis of components is releted to people's physical health and social harmony and stability.Traditional detection methods(such as chromatography,spectroscopy and electrophoresis,etc.)are characterized by expensive equipment,complicated pretreatment,high cost and slow speed,which often consume a lot of manpower,material resources and time.Electrochemical sensing analysis and detection technology has the advantages of high sensitivity,rapid response,high stability,easy miniaturization,etc.,and is widely used in the analysis and detection of food,drugs,environment,drugs,poisonants and other fields.The performance of the electrochemical sensor depends on the electrode modification materials and the structure of the electrode catalyzed surface.Transition metal compound/carbon composite has the characteristics of high catalytic activity,high electrical conductivity,large specific surface area,good stability,economy and easy availability,etc.,which are electrode modification materials with broad application prospect.In this paper,three different transition metal compounds/carbon composites were designed and prepared,with which three modified sensor electrodes,Ti₃C₂T_X/MWCNTs/GCE,MoS₂/rGO/GCE and CuInSe₂/Carbon Spheres/GCE,were constructed respectively for highly sensitive detection of morphine(MOP),acetaminophen(ACOP)and dopamine(DA)respectively.The main conclusions are as follows:1.Transition metal carbides(MXenes)Ti₃C₂T_Xwere prepared by hydrofluoric acid(HF)etching the original phase Ti₃AlC₂.After acidified treatment,MWCNTs were mixed with Ti₃C₂T_Xby ultrasonic mechanical mixing method.Ti₃C₂T_X/MWCNTs/GCE modified electrode towards MOP was constructed by drop casting method.The results show that Ti₃C₂T_Xhad accordion-like structure,and there were a lot of-OH,-F,and=O functional groups on the surface of Ti₃C₂T_X,which were helpful to adsorb MOP to the surface of the electrode.Furthermore,these functional groups could also interact with the functional groups on the surface of MWCNTs to accelerate the electron transfer between the target analytes and transducer and improve the electrical conductivity of the composite material.The electrochemical performance of Ti₃C₂T_X/MWCNTs/GCE sensing platform was studied by using CV,DPV and EIS electrochemical measurement methods.The results show that Ti₃C₂T_X/MWCNTs/GCE exhibited good detection performance with the linear detection range of 0.01?100?M,and the detection limit of 0.0092?M(S/N=3).The sensor had good stability,repeatability and anti-interference.2.Using Na₂MoO₄as molybdenum source and L-cysteine as sulfur source,MoS₂/rGO composites were prepared by one-step hydrothermal method,and MoS₂/rGO/GCE sensing electrode tewords ACOP was constructed by drop casting method.The results show that the nano-flower spherical MoS₂growed uniformly in situ on the rGO folded nanosheets,which greatly increased the surface area and active site of the modified electrode.The interaction between MoS₂and rGO is beneficial to improve the electrochemical catalytic reaction rate Electrochemical test results show that the MoS₂/rGO/GCE sensor had a good detection result for ACOP,with a wide linear range(0.005?300?M)and a low detection limit(0.0017?M,S/N=3).The sensor had good stability,repeatability and anti-interference.3.The CuInSe₂/Carbon Sphere composite was prepared by one-step solvothermal method using glucose as the precursor,and the CuInSe₂/Carbon Sphere/GCE sensor electrode was constructed by drop casting method for DA analysis and detection.The results show that the two-dimensional petal-like structure of CuInSe₂growed uniformly on the carbon spheres,which increased the active area and the number of active sites,and was beneficial to improve the electrochemical catalytic reaction rate.The redox adjustability of Cu improves the adsorption and redox rate of DA on the electrode surface,thus reducing the redox potential and improving the sensitivity of the sensor.The electrochemical test results showed that the CuInSe₂/Carbon Sphere/GCE sensor had a high electrocatalytic activity for DA with a linear range of 1?800?M and a detection limit of 0.59?M(S/N=3).