表面增强拉曼散射基底制备及其在农药残留检测中的应用

发布时间：2018-08-27 12:00

【摘要】：近年来,农药残留问题越来越成为社会关注的焦点,表面增强拉曼光谱技术作为一种快速、简单、高灵敏度的检测手段在农残检测领域拥有其独特的优势。表面增强拉曼散射技术(SERS)的关键是其增强基底的制备,本文首先用柠檬酸钠还原法制备了银溶胶和金溶胶。详细探索了最佳制备条件,得出制备银溶胶的最佳条件为:硝酸银与柠檬酸钠以1:4摩尔比例在PH=3的酸性条件下加热反应14 min;制备金溶胶的最佳条件为:硝酸银与氯金酸以2:3质量分数比在PH=4的弱酸性条件下加热反应15 min。然后结合密度泛函理论,采用B3LYP/6-31G基组对高效氯氟氰菊酯和联苯菊酯分子进行空间构型的优化和理论拉曼光谱的计算。理论拉曼光谱与实验测得拉曼光谱显示出较好的一致性。结合理论拉曼光谱,分别在400~1800 cm-1和400~1500 cm-1区间对高效氯氟氰菊酯和联苯菊酯的部分拉曼特征峰作了相应的谱峰归属指认。最后以金桔为研究对象,分别以金、银溶胶为增强基底,在便携式光纤拉曼探测系统下得到了金桔表皮高效氯氟氰菊酯和联苯菊酯两种农药各45个不同浓度梯度的拉曼光谱数据。对原始光谱进行基线校正和小波去噪处理后建立了联合区间偏最小二乘法定量分析模型。高效氯氟氰菊酯含量预测的最优模型的相关参数为:预测均方根误差RMSEP=1.6531mg/L,相关系数Rp=0.9979;联苯菊酯含量预测的最优模型的相关参数为:RMSEP=1.7142mg/L,Rp=0.9931。
[Abstract]:In recent years, pesticide residue has become the focus of attention. As a rapid, simple and sensitive method, surface-enhanced Raman spectroscopy has its unique advantages in the field of detection of pesticide residues. The key of surface-enhanced Raman scattering (SERS) technique is the preparation of the enhanced substrate. In this paper, silver sol and gold sol were prepared by sodium citrate reduction method. The optimum preparation conditions were explored in detail. The optimum conditions for the preparation of silver sol were obtained as follows: silver nitrate and sodium citrate reacted at 1:4 molar ratio under the acid condition of PH=3 for 14 min; to prepare gold sol. The optimum conditions were as follows: the ratio of silver nitrate and chlorgold acid was 2:3 in PH=4. Heating reaction for 15 min. under weak acidic conditions Based on density functional theory (DFT), the spatial configuration of high efficiency cypermethrin and bifenthrin molecules were optimized by using B3LYP/6-31G basis group and the theoretical Raman spectra were calculated. The theoretical Raman spectra are in good agreement with the experimental Raman spectra. Combined with theoretical Raman spectra, some Raman characteristic peaks of high efficiency cypermethrin and bifenthrin were assigned in the range of 400 ~ 1800 cm-1 and 400 ~ 1 500 cm-1, respectively. At last, the gold and silver sol were used as the enhancement substrate. The Raman spectra data of 45 different concentrations of fenpropathrin and bifenthrin were obtained by a portable fiber Raman detection system. After baseline correction and wavelet denoising, the quantitative analysis model of joint interval partial least square method is established. The correlation parameters of the optimal model for prediction of high efficiency cypermethrin content are as follows: the RMSEP=1.6531mg/L, correlation coefficient of root mean square error (RMSEP=1.6531mg/L,) is the best model for predicting the content of bifenthrin in Rp=0.9979;. The correlation parameter of the optimal model for predicting the content of permethrin is 1. 7142mg / L rptran 0.9931.
【学位授予单位】：暨南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O657.37;TQ450.263

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