|浙江大学学报(农业与生命科学版) 2017, 43(3) 329-340 DOI: 10.3785/j.issn.1008-9209.2016.10.031 ISSN: 1008-9209 CN: 33-1247/S|
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|摘要： 基于孔雀石绿对水溶性CdTe/ZnS量子点存在荧光猝灭现象,建立了一种用于水产养殖违禁添加孔雀石绿残留检测的新方法。在pH 8.0、0.065 mol/L的Tris-HCl缓冲溶液及1.60×10－4 mol/L的CdTe/ZnS量子点优化体系中，在0.019 3～1.28 mg/L范围内，孔雀石绿质量浓度与水溶性量子点CdTe/ZnS的荧光猝灭强度呈良好的线性关系，相关系数r =0.999，检出限为0.005 43 mg/L。该方法可成功用于淡水和海水养殖用水以及鱼肉组织中违禁添加孔雀石绿残留的测定，添加回收率为90.4%～100.3%，相对标准偏差为0.37%～1.01%。该方法对水产品和养殖用水的检测结果与液质联用法的检测结果一致，且假阳性和假阴性率试验结果也均与真实样品一致：说明水溶性量子点荧光探针法对孔雀石绿残留检测特异性较好。通过紫外-可见吸收光谱及共振光散射技术研究孔雀石绿对水溶性CdTe/ZnS量子点荧光猝灭特征，发现其荧光猝灭机制是CdTe/ZnS量子点与孔雀石绿相互作用，从而建立起共振能量转移体系。|
|关键词： 水溶性量子点 荧光探针 孔雀石绿 荧光猝灭|
|Quantitative determination of illegally added malachite green residues in aquaculture using water-soluble quantum dots as fluorescent probes|
|XIE Xiaomei, LIAO Min*, HUANG Yu, YE Zhaojin, LÜ Ting|
|(Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China)|
Quantum dots have unique physical and chemical properties and optical properties due to its special structure. In recent years, as a new type of fluorescent probe materials applied in chemical and biological analysis, medical diagnosis and other fields, quantum dots have become the focus of research. At present, some studies have been reported on the detection of heavy metal, veterinary drug and pesticide residues in food by using quantum dots as fluorescent probes. Related research reports showed that the use of quantum dots as a fluorescent probe to analyze the analyte with impact of food safety had advantages of high sensitivity, good selectivity, short response time, and less investment, which indicated the quantum dots as a fluorescent probe had wide application prospects in food safety inspection field. The malachite green had good antibacterial effect and low price, which was often illegally used in aquaculture as insecticides and fungicides. The malachite green had the potential carcinogenic effects, which was clearly listed in Chinese Food Animal Banned Veterinary Drugs and Compounds List in 2002, but in fact, malachite green residue has been detected in aquatic products breeding from time to time due to illegal addition. Malachite green residue detection method has been mainly reported, such as high performance liquid chromatography, surface enhanced Raman scattering spectroscopy, liquid chromatography-mass spectrometry (LC-MS), ultraviolet spectrometry, which were not easy to be applied and popularized at the basic unit, due to lower sensitivity, or longer single sample detection time, or expensive equipment, or complicated operation. Therefore, it was urgent to develop a detection method with high sensitivity, good selectivity, short response time and less input. Quantum dot fluorescent probe method in residue detection had the potential to meet the demand, but the current studies using the method of quantum dots to detect malachite green were rarely reported. |
In view of this, based on the application prospects of residue detection by quantum dot fluorescent probe method in the field of food safety, the feasibility of detecting malachite green residue with illegal addition in aquaculture was researched in the present study by a water-soluble quantum dot fluorescent probe method, and the purpose was to establish a method to detect trace residues of malachite green in actual water and fish products.
In this study, water-soluble CdTe/ZnS quantum dot fluorescent probe was synthesized under mild conditions with 3-mercaptopropionic acid as a stabilizer. The main influence factors of water-soluble CdTe/ZnS quantum dot fluorescent probe to detect malachite green in the detection system were investigated, including buffer system type, buffer pH, buffer concentration, concentration of quantum dots, reaction time, concentration of malachite green, coexisting ions, etc. The best condition was obtained for the water-soluble CdTe/ZnS quantum dot probe method to detect malachite green on the basis of above investigation. Under the optimal detection condition, water-soluble CdTe/ZnS quantum dot fluorescent probe for quantitative detection of trace residues of malachite green was carried out in water and fish products. At the same time, the mechanism of water-soluble CdTe/ZnS quantum dot fluorescent probe method being used for the detection of trace residues of malachite green was studied by using ultraviolet-visible (UV-Vis) absorption spectroscopy and resonance light scattering technique.
As a result, a simple, rapid and sensitive approach to quantitative determination of illegally added malachite green residues in aquaculture was developed based on the fluorescence quenching of water-soluble CdTe/ZnS quantum dots by malachite green. Under the optimized conditions, i.e., pH=8.0, 0.065 mol/L Tris-HCl and 1.60×10－4 mol/L CdTe/ZnS in the detection system, the linear range of water-soluble CdTe/ZnS quantum dot fluorescent quenching intensity versus the concentration of malachite green from 0.019 3 mg/L to 1.28 mg/L, with a correlation coefficient of r=0.999 and a limit of detection of 0.005 43 mg/L. The proposed method had been applied to quantitative determination of malachite green in muscle tissue of fish and water for freshwater and marine aquaculture successfully, with the recovery percentage of 90.4%-100.3% and relative standard deviations of 0.37%-1.01% for added malachite green. The detection results of aquatic products and aquaculture water were consistent with the results of LC-MS method, while the results of false positive rate and false negative rate test were the same with real samples, which indicated that the water- soluble quantum dot fluorescent probe method of malachite green residue detection was more specific. The fluorescence quenching mechanism was further investigated by using UV-Vis absorption spectra and resonance light scattering. The results indicated that the fluorescence quenching of water-soluble CdTe/ZnS quantum dots by malachitegreen was due to fluorescence resonance energy transfer system being constructed between CdTe/ZnS quantum dots (donor) and malachite green (acceptor).
|Keywords: water-soluble quantum dots fluorescent probe malachite green fluorescence quenching|
|收稿日期 2016-10-03 修回日期 网络版发布日期 2016-11-20|
|1．李刚，都林娜，许方程，王阳，泮琇.肠杆菌CV-b脱色孔雀石绿的特性及机制[J]. 浙江大学学报(农业与生命科学版), 2017,43(4): 493-501|
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