摘要
农药残留污染使得食品安全获得广泛关注,发展快速准确和高灵敏的农药残留检测新方法,具有一定的理论和实际意义。利用金纳米在聚集和分散状态下,等离子吸收光谱的变化以及荧光分子罗丹明110与金纳米吸收光谱产生内滤效应,设计了比色和荧光双模式光学传感器用于农药残留的高灵敏检测。采用柠檬酸盐还原法合成直径约13 nm表面带有负电荷的金纳米粒子,在水溶液中呈分散状态,呈酒红色,溶液的最大吸收波长在520 nm处。农药分子可与金纳米通过形成Au-N或者Au-O配位键而结合,导致分散的金纳米在农药分子诱导作用下发生聚集,溶液颜色逐渐由酒红色变为蓝紫色,520 nm处的吸光度逐渐降低,根据溶液吸光度的变化即可实现农药含量的测定。溶液颜色的显著变色即便裸眼也可以观察,该检测方式具有简便、快速和成本低的优势。尽管单一的比色检测模式简单,但存在假阳性的可能。为进一步验证结果的准确性,同时提高检测的灵敏度,在金纳米溶胶中引入带正电的荧光染料罗丹明110,其吸附在带负电荷的金纳米表面,此时金纳米在溶胶仍处于良好的分散状态。由于罗丹明110的荧光光谱与金纳米的吸收光谱重叠,即二者发生了荧光的内滤效应,此时溶液的荧光强度很弱,甚至不发射荧光。一旦溶液中存在农药分子,与金纳米表面的荧光染料竞争吸附,从而诱导金纳米聚集,溶液由酒红色变为蓝紫色,同时释放到溶液中的罗丹明110分子的荧光得以恢复,根据溶液吸光度和荧光强度变化实现对目标物的比色和荧光双模式检测。以辛硫磷为模型分子,测试该传感器的各项性能,比色法和荧光法的检出限分别为15.0和4.0 nmol·L^(-1),实际样品测试结果表明,该传感器在食品安全检测中具有一定的应用潜力。
Food safety has attracted public attention because of pesticide residue contamination.It has certain theoretical and practical significance to develop fast,accurate and highly sensitive new methods for detecting pesticide residues.In this paper,a colorimetric and fluorescent dual-mode optical sensor has been designed for sensitive detection of pesticide residues by using the difference of plasma absorption spectrum of aggregation and dispersion gold nanoparticles and the internal filtration effect between fluorescent molecule rhodamine 110 and gold nanoparticles.Gold nanoparticles(AuNPs)with a diameter of about 13 nm and a negative charge on the surface were synthesized by the citrate reduction method.They were dispersed in an aqueous solution and showed wine red.The maximum absorption wavelength of the solution was 520 nm.Pesticide molecules can induce the aggregation of dispersed AuNPs by forming Au-N or Au-O coordination bonds,resulting in the color changes of the solution gradually from redwine to blue-purple.Pesticide content can be detected according to the change of absorbance of the solution at 520 nm.The significant color change of the solution can be observed even with the naked eye.The detection method has the advantages of simplicity,rapidity and low cost.Although the single colorimetric detection mode is simple,false positive is possible.In order to further verify the accuracy of the results and improve the detection sensitivity,fluorescent dye rhodamine 110 with the positive charge is introduced into the dispersed AuNPs solution,which can adsorb on the negatively charged AuNPs surface.In this state,the AuNPs are still well dispersed in the solution.The fluorescence spectrum of rhodamine 110 overlaps with the absorption spectrum of AuNPs,leading to the fluorescence internal filtration effect(IFE).The fluorescence intensity of the solution is very weak,even with no fluorescence emission.In the presence of pesticide molecules in the solution,they compete for adsorption with the fluorescent dyes on the surface of AuNPs to induce the aggregation of AuNPs.The color of the solution changes from redwine to blue purple.At the same time,the fluorescence of rhodamine 110 molecules released into the solution is restored.The colorimetric and fluorescence dual-mode detection of the targets is realized according to the changes insolution absorbance and fluorescence intensity.As a model molecule,phoxim was used to test the sensor's performance.The limit of detection for color imetry and fluorescence were 15.0 and 4.0 nmol·L^(-1),respectively.The test results of actual samples showed that the sensor had certain application potential in the food safety field.
作者
朱少昊
孙学萍
谭婧盈
杨东旭
王海霞
王修中
ZHU Shao-hao;SUN Xue-ping;TAN Jing-ying;YANG Dong-xu;WANG Hai-xia;WANG Xiu-zhong(College of Chemistry and Pharmaceutical Sciences,Qingdao Agricultural University,Qingdao 266109,China;College of Grassland Science,Qingdao Agricultural University,Qingdao 266109,China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2023年第9期2785-2791,共7页
Spectroscopy and Spectral Analysis
基金
国家级、省级大学生创新创业项目(202110435184,S202010435055),山东省高等教育本科教学改革研究项目(Z2021220),山东省高等学校青创人才引育计划项目,青岛农业大学教学改革项目(ZCJG202105,XJY2021021)资助。
关键词
比色法
荧光法
双模式
农药残留
传感器
Colorimetry
Fluorescence
Dual-modes
Pesticide residue
Sensor
作者简介
朱少昊,1999年生,青岛农业大学化学与药学院本科生,e-mail:642278247@qq.com;通讯作者:王海霞,e-mail:hxwang@qau.edu.cn;通讯作者:王修中,xzwang@qau.edu.cn。
