The Development, Evaluation And Application Prospect Of Microfluidic Chemoluminescence Enzyme Sensor

China is a large agricultural country, organophosphate and carbamate pesticides are widely used in agricultural production due to the high efficiency, low toxicity, readily biodegradable, etc. long-term consumption by excessive pesticide residues in fruits and vegetables, there will be a series of neurotoxic symptoms,such as ataxia, speech disorders, mental confusion, sweating, tremors, and even cause death. Pesticide residues also brought serious environmental pollution. Implement effective monitoring of organophosphorus and carbamate pesticides in order to ensure people’s health is important.At present, the pesticide residue analysis method mainly gas chromatography, high performance liquid chromatography, electrophoresis, high performance liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry, can not be vegetables, fruits and other food production, sales links comprehensive and effective monitoring, can not effectively prevent high pesticide residues in fruit and vegetable market. Actively carry out pesticide residues in food rapid detection technology-sensor for the protection of our people’s food security is of great significance.With immobilized acetylcholinesterase (AChE) working as the recognition element, microfluidic chip as flow reaction cell. a novel flow analysis chemiluminescence (CL) sensor for the detection of organophosphorous and carbamate pesticides was developed and optimized. The details of the contents and results of the thesis are as follows:1 The organic polymer polymethyl methacrylate (PMMA) was used as the material for fabricating microfluidic chip, which consisted of a base plate with the size(55mmx 35mmx3mm) and a cover plate with the size (55mm×35mm×3mm). We adopted the milling machining to produce the micro structure. The base chip has a spiral channel and two holes of diameter 1.8 mm. The channel, with the width of 0.8 mm, the depth of 1 mm and the space between channels of 0.8 mm, was produced by etching. Two holes were used as the inlet (center) and outlet (side), respectively. The bonding of chip was accomplished by solvent bonding method at room temperature.The procedures were as follows:the base plate and cover plate were cleaned with ultrasound in anhydrous alcohol/water (1:1, V/V) mixture for 10 min. After the chip dried, a few drops of dichloroethane/Anhydrous ethanol (1:1, V/V) mixture was added on the contact surface of the cover plate and coated uniformly. Then, the base plate and cover plate were aligned, and placed on the thermocompressor for 5 minutes. After bonding, fuchsin solution was injected into the micro tube and no leakage is found, which indicates that the chip’s contact was compact after the bonding. Then the chip was dropped down freely from a height of 2 m onto the concrete floor and the chip was intact, and the strength of the chip was over 100 N/cm2, which indicates that the impact strength of the bonding meets the requirement.2 In this study, the flow injection-chemiluminescence systems, including a reactor with immobilized AChE on CNBr-activated Separose 4B and a miniaturized flow cell detector, was proposed for the detection of organophosphate and carbamate pesticides. Research to optimize the sensor parameters:luminol and potassium ferricyanide concentration, flow rate, pesticides suppression time, substrate concentration, enzyme resurrection time, and the substrate with the enzyme contact time. Under the best conditions, respectively, leads to different concentrations of dichlorvos, phoxim, chlorpyrifos, dimethoate, carbaryl, carbofuran, methomyl standard solution, draw the standard curve.3 Further from stability, reproducibility, precision indicators to comprehensive measure of the performance of the sensor, come to the the sensor excellent performance, good stability, high reproducibility. Sensor for detection cabbage and apples pesticide residues, The results display the biosensor has good recovery (>85%) and reproducibility (RSD<8.1%). the former treatment is simple. In addition, the advantages and disadvantages of the sensor of the proposed model, planning the future direction of development of the product.