Development And Application Of Multi-walled Carbon Nanotubes Modified Molecularly Imprinted Electrochemical Sensor

Molecular imprinting technology(MIT) refers to the preparation of a specific target molecule(template molecule or imprinted molecule) selectively with specific polymers that molecularly imprinted polymer(MIP), it’s often described as a way of making a molecular lock to match a molecular key. Compared with other techniques,and because of their structure-activity predetermination, specific recognition and extensive practicability, molecularly imprinted technology is development so rapidly. At present, the preparation and application of molecularly imprinted membranes has caused widespread concern related to researchers. The development and application of molecularly imprinted polymeric(MIP) membranes have been the one most attracting assignment in its study. MIP membrane is a kind of high selectivity and stability of the synthetic receptors. And electrochemical sensor could offer with possibility of easy design, quick preparation, high sensitivity and speed, at low cost, easy operating, manufacture, automation and miniaturization. Thus the molecularly imprinted polymer film used as recognition elements to prepare a new generation of electrochemical sensors and biosensor has important research significance. In addition, with nanometer materials modified electrode and the introduction of nanometer materials to electrochemical sensors and biosensors is a hot topic for research.In this thesis, we are trying to combine the high selectivity and stability of molecularly imprinted polymer, special effects of nanometer materials and modern electrochemical technology, successfully prepared a series of molecularly imprinted matrix as the sensitive element of new electrochemical sensors. Also, MIP sensors are characterized and researched by the technology of DPV, CV, UV, IR, SEM, EIS, et al. The main research work of this thesis is as follows:1、Serotonin(5-HT) is an essential kind of neurotransmitter for the human body. It will also affect the person’s appetite, appetite, sleep and mood. We were successfully constructed a new molecularly imprinted electrochemical sensor which using 5-HTP as a template molecule based on the detection of 5-HT in this chapter. The linear relationship between current and concentration of 5-HT were obtained in the range from 1.8×10-6 mol L-1 to 5.4×10-9 mol L-1, with the linear regression equation Ip=1.552C+8.778×10-8(I:μA,C:μmol L-1), a correlation coefficient of 0.9997. The detection limit of 1.8×10-10 mol L-1 was achieved(S/N=3). The applicability of the modified electrode was demonstrated by determination of 5-HT in human serum. In addition, the oxidation mechanism of its potential is discussed.2 、 A novel modified carbon paste electrode(CPE) is prepared as an electrochemical voltammetric sensor based on molecularly imprinted polymer for sunset yellow(SY) detection. Carbon nanotubes, molecular imprinted polymers(MIPs) were doped into the carbon paste, functioned as a recognition element constructed sunset yellow electrochemical sensors. Compared with the molecularly non-imprinted polymer carbon paste electrode(NIP-CP), the MIP-CP electrode exhibited very high recognition ability. Under the optimal conditions, the linear relationships between current and concentration were obtained in the range from 6×10-6 mol L-1 to 8×10-8 mol L-1, with the linear regression equation Ip=-3.23C-5.34×10-7(I:μA, C:μmol L-1), correlation coefficient 0.9985. The detection limit of 3.627×10-9 mol L-1 was achieved(S/N=3). The modified electrodes can also be used in the detection of sunset yellow dye in beverages.3、This part of the thesis using molecular imprinting technique, with tartrazine(TT) as the template molecules, acrylamide(AM) as functional monomer, in the surface of a glassy carbon electrode modified with multi-walled carbon nanotubes by in situ polymerization method electric successfully constructed a molecularly imprinted electrochemical sensor for the detection of TT. The sensor’s linear response range was between 8×10-7 mol L-1 to 8×10-8 mol L-1 and 1×10-5 mol L-1 to 1×10-6 mol L-1, with a detection limit of 2.74×10-8 mol L-1. This method not only had good selectivity, high sensitivity and good reproducibility but also was a relatively simple and controllable method to detect TT.