基于纳米材料比色法与微流控的农药检测技术研究

发布时间：2018-07-08 15:21

本文选题：农药检测 + 微流控芯片　；参考：《江苏大学》2017年硕士论文

【摘要】：由于微流控芯片尺寸小、样品少、检测信号微弱且极易受外界环境干扰,农药检测检出限高、灵敏度低。因此,本文从纳米材料和芯片结构2大方面,建立了纳米材料比色法,利用Comsol微混合仿真和对比试验设计验证了高效的微流控芯片结构,研究开发了低检出限、高灵敏度实用方便的农药检测方法和技术,对于保障食品安全具有重要意义。主要的研究内容和结论如下:(1)建立了基于铁酸铜/石墨烯量子点(CuFe_2O_4/GQDs)比色法。采用一步水热法制备了CuFe_2O_4/GQDs纳米材料,并对其进行表征验证和性能测试。试验结果表明,与CuFe_2O_4、GQDs单体相比,CuFe_2O_4/GQDs具有较高的催化活性。通过动力学研究发现,CuFe_2O_4/GQDs较天然的辣根过氧化物酶(HRP)对反应底物H_2O_2和TMB有更好的亲和力。此外,对微量的中间产物H_2O_2进行检测验证,建立了吸光度和H_2O_2浓度之间的线性方程为A=0.04449+0.000786783CH_2O_2(C:m M),R2为0.98977,检出限为6.7×10-4 M。(2)研究微流控芯片几何结构分别与微混合及反应效率的关系。在局部微混合几何结构方面:基于微流体拉伸、压缩、折叠、分流等思想,设计了3大类微混合结构,通过Comsol微混合仿真对比验证得出基于矩形内肋复合圆形循环分合型(“矩形-圆形”)结构混合效果最佳。最佳内肋长度L为550mm,圆形直径d1为400mm,与其它2类最佳的矩形内肋型和圆形循环分合型微混合机构相比,混合效果分别提高了17.12%和39.48%;在整体芯片几何结构方面:设计了基于不同反应策略的2种整体芯片结构,对比试验得出,“伞型”结构比“鱼鳞型”结构检测耗时缩减17.65%,而后者比前者反应效率提高20.93%。综合考虑,采用“矩形-圆形”微混合结构设计的“鱼鳞型”微流控芯片。(3)对构建的微流控农药检测平台进行试验分析。优化了主要的试验条件参数。综合考察该试验平台的农药检测线性度、灵敏度、检出限及选择性等指标。最后,对实际样品进行实用性测试。试验结果显示,吸光度值与毒死蜱农药浓度在2.0×10-8~6.0×10-7 M内呈现良好的线性关系。线性方程为A=0.61822-0.000855261CChlorpyrifos(C:nM),R2为0.99758,最低检出极限为1.01×10-8M,灵敏度为855.261 a.u.·mM-1,该方法具有良好的选择性。此外,对农药在番茄、梨和河水实际样品的加标回收率范围在91.2%~115%之间,实用性能较好,可用于实际样品检测。
[Abstract]:Because the microfluidic chip is small in size, few samples, weak detection signal and easy to be interfered by the outside environment, the detection limit of pesticide is high and the sensitivity is low. Therefore, the colorimetric method of nanomaterials is established from two aspects of nanomaterials and chip structures. The high efficient microfluidic chip structure is verified by Comsol micromixing simulation and contrast test, and the low detection limit is developed. High sensitivity, practical and convenient pesticide detection methods and techniques are of great significance to ensure food safety. The main contents and conclusions are as follows: (1) the colorimetric method based on CuFe2O4 / GQDs was established. CuFeS _ 2O _ 4 / GQDs nanomaterials were prepared by one-step hydrothermal method and characterized and tested. The results show that CuFe2O4GQDs have higher catalytic activity than CuFe2O4GQDs. The kinetic study showed that the CuFe2O4 / GQDs had better affinity to the reaction substrates H _ S _ 2O _ 2 and TMB than the natural horseradish peroxidase (HRP). In addition, the linear equation between the absorbance and the concentration of H _ 2O _ 2 is established as A0.04449 0.000786783CHS _ 2O _ 2 (C: M M) and R ~ 2 = 0.98977, and the detection limit is 6.7 脳 10 ~ (-4) M. (2) the relationship between the geometric structure of the microfluidic chip and the micromixing and reaction efficiency is studied, and the detection limit is 6.7 脳 10 ~ (-4) M ~ (-1). (2) the relationship between the geometric structure of the microfluidic chip and the reaction efficiency is studied. In the aspect of local micro-mixing geometry, three kinds of micro-mixed structures are designed based on the ideas of micro-fluid stretching, compression, folding and shunt. The results of Comsol micro-mixing simulation show that the mixed effect of rectangular internal rib composite circular split-type ("rectangle-circular") structure is the best. The optimum internal rib length L is 550 mm and the circular diameter D 1 is 400 mm. Compared with the other two kinds of optimal rectangular internal rib type and circular split-type micromixing mechanism, the optimum internal rib length is 550mm and the circular diameter is 400mm. The mixing effect was improved by 17.12% and 39.48%, respectively. In terms of the geometric structure of the whole chip, two kinds of integrated chip structures based on different reaction strategies were designed and compared with each other. The "umbrella" structure was 17.65 less than the "fish scale" structure, while the latter was 20.933 higher than the former. The "fish scale" microfluidic chip was designed with "rectangular circular" microfluidic chip. (3) the experimental analysis of the microfluidic pesticide detection platform was carried out. The main parameters of test conditions are optimized. The linearity, sensitivity, detection limit and selectivity of pesticide detection were investigated. Finally, the practicability of the actual samples is tested. The results showed that there was a good linear relationship between the absorbance of chlorpyrifos and the concentration of chlorpyrifos in the range of 2.0 脳 10 ~ (-8) ~ 6.0 脳 10 ~ (-7) M. The linear equation is Acan0.61822-0.000855261CChlorpyrifos (C: nM) R2 is 0.99758, the lowest detection limit is 1.01 脳 10 ~ (-8) Mand the sensitivity is 855.261 a.u.mM-1.The method has good selectivity. In addition, the recoveries of pesticides in tomato, pear and river water samples ranged from 91.2% to 115%.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3;TQ450.263

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