摘要
利用光谱法、Benesi-Hildebrand法、热力学方法研究β-环糊精(β-CD)及其衍生物对黄曲霉毒素B1(AFB1)荧光增强机理,探讨溶剂中甲醇体积比、M-β-CD浓度、时间、干扰离子等因素对荧光增强作用的影响。根据Benesi-Hildebrand法确定7种β-环糊精及其衍生物在低浓度时与AFB1包络比为1:1,高浓度时包络比为2:1。采用热力学方法计算了包合常数最大的M-β-CD与AFB1包合过程的熵变(ΔS)、焓变(ΔH)及自由能变化(ΔG)均为负值,说明包合反应是放热反应且能自发进行,焓变是形成超分子包络物的主要驱动力。紫外吸收光谱及KI淬灭实验表明AFB1进入M-β-CD空腔从而使荧光得到保护。得出结论:7种β-环糊精及其衍生物与AFB1通过形成超分子包络物可大幅增强AFB1荧光发射强度,提高AFB1荧光分析法的检测灵敏度。
The mechanisms underlying fluorescence enhancement of aflatoxin B1（AFB1） by β-cyclodextrin（β-CD） and its derivatives were explored using spectroscopy,Benesi-Hidebrand analysis and thermodynamics.Moreover the effects of methanol volume percentage,M-β-CD concentration,reaction time and interfering ions on fluorescence enhancement were analyzed.β-CD and its six derivatives showed an inclusion ratio to AFB1 of 1：1 at low concentrations and 2：1 at high concentrations.The thermodynamic parameters entropy change（ΔS）,enthalpy change（ΔH） and free energy change（ΔG） for maximum inclusion constant between M-β-CD and AFB1 were negative,suggesting that the inclusion reaction is exothermic and can occur spontaneously.Enthalpy change was the dominant force during the formation of inclusion complexes.UV absorption spectra and KI quenching experiments showed that AFB1 could enter M-β-CD cavity to protect fluorescence.Therefore,β cyclodextrin and its derivatives can allow considerable enhancement in the fluorescence emission intensity of AFB1 by the formation of supramolecular inclusion complexes,resulting in increased sensitivity of AFB1fluorescence analysis.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2012年第15期28-33,共6页
Food Science
基金
国家"863"计划项目(2007AA10Z427)
中央高校基本科研业务费专项(XDJK 2009C056)
西南大学研究生科技创新基金项目(ky2010006)
关键词
Β-环糊精
AFB1
荧光增强
超分子包络物
β-cyclodextrin
aflatoxin B1
fluorescence enhancement
supramolecular inclusion
