| Acetaminophen is a conventional,fast-acting antipyretic analgesic with few side effects.However,overdose can lead to liver toxicity and even liver failure.Therefore,the detection of acetaminophen levels in the environment,biological fluids and pharmaceuticals is of great importance to human health.Traditional methods for detecting acetaminophen content include capillary electrophoresis,fluorescence spectroscopy and Raman spectroscopy.The advantages of these traditional methods are their high specificity and fast response time,but the disadvantages are the high cost and complicated operation.In order to make up for these shortcomings,electrochemical detection of acetaminophen has gradually developed into a research hotspot in recent years,and its operation is simpler and more sensitive than traditional detection methods and the device is more easily miniaturized.However,electrochemical detection also suffers from the difficulties of selectivity,stability and reproducibility,and here the concept of molecular imprinting is introduced.Molecular imprinting technology（MIT）is a technique with specific recognition function that mimics antibody-antigen interaction,and its recognition is not affected by external environmental changes,and it has started to develop rapidly in different fields because of its advantages such as predetermination,specificity and practicality.The combination of molecular imprinting technology and electrochemical detection combines the advantages of high sensitivity of electrochemical sensors and high selectivity of molecularly imprinted polymers.This innovative detection method miniaturizes the sensor device while giving controlled thickness and specific surface topography to the imprinted polymers.Currently,molecularly imprinted electrochemical detection is receiving more and more public attention,where the composite of modified materials with molecularly imprinted electrochemical sensors can provide more reactive area to the device and significantly enhance the sensing performance of the device.Nanocomposite modification materials are the best materials for modification sensors due to their unique optical,thermal and magnetic properties.In this thesis,a molecularly imprinted electrochemical sensor with high selectivity and high sensitivity for the detection of acetaminophen was developed by combining the advantages of nanocomposites,electrochemical detection and molecular imprinting techniques.The main work of this thesis is as follows:In this paper,imprinted poly（o-phenylenediamine）films were prepared by a simple cyclic voltammetry method using o-phenylenediamine（o-PD）as the functional monomer and acetaminophen（AP）as the template molecule.The surface morphology of the imprinted polymer was observed by field emission scanning electron microscopy（SEM）,cyclic voltammetry（CV）and electrochemical impedance spectroscopy（EIS）were selected to perform electrochemical testing of the sensor,and potassium ferricyanide molecules were introduced as electrochemical probes to indirectly quantify the concentration of AP by the reduction current of potassium ferricyanide,and the sensor performance was evaluated by differential pulse voltammetry（DPV）.The sensing mechanism of the sensor is the electropolymerization of o-PD in the presence of AP to form a poly-o-PD film embedded with AP molecules,and the AP is eluted from the poly-o-PD film in a specific way to form a cavity with specific recognition of AP on the surface of the poly-o-PD film,thus achieving the specific detection of acetaminophen.Meanwhile,due to the excellent mechanical stability of poly-o-PD,the reproducibility and stability of the sensor are ensured.The prepared molecularly imprinted electrochemical sensor exhibited excellent sensing performance with a detection range from 1.0×10-6M to 1.5×10-5M.The detection limit was as low as 2.5×10-6M.In addition,the sensor maintained 88%of the initial current response for 20 days with good temporal stability and reproducibility,and showed good performance against common interferents（dopamine,ascorbic acid,phenol,lactic acid,etc.）.The use of this sensor for the detection of acetaminophen content in drugs shows the excellent utility of the sensor.In this work,a reduced graphene oxide co-blended gold nanoparticle high-performance composite modified molecularly imprinted electrochemical sensor was prepared for the direct,rapid and selective detection of acetaminophen based on the first work.The reduction of gold compounds and graphene oxide at a glassy carbon electrode combines the excellent electrocatalytic activity of nanoparticles with the outstanding selectivity of molecular imprinting,thus streamlining the experimental steps and avoiding the incorporation of electrochemical probes,enabling the direct oxidative reduction of acetaminophen at the electrode surface.Acetaminophen as a template molecule and o-phenylenediamine as a monomer providing specific functional groups were used to electropolymerize stable poly-o-PD films on nanoparticle-modified electrodes,and the surface morphology of the imprinted films was observed by field emission scanning electron microscopy,while cyclic voltammetry and electrochemical impedance spectroscopy were used to probe the performance of the sensors in an electrochemical environment and analyze the electrochemical properties of the sensors to confirm the successful The sensing performance of the device was evaluated by differential pulse voltammetry.In comparison with the simple imprinted sensor,it was found that the reduced graphene oxide co-blended with gold nanoparticles could significantly increase the sensitivity of the sensor with an operating range of 5.0×10-9M to 5.0×10-4M and a lower detection limit as low as 5.0×10-9M.The sensor was also able to maintain 84%of the initial current response over a long period of 25 days and remained stable over 5repetitions.The practical applicability of the device was demonstrated during the detection of acetaminophen content in common cold medicines. |
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