机构地区:[1]福州大学材料科学与工程学院分子材料与工程系,福建福州350108
出 处:《光谱学与光谱分析》2024年第9期2459-2466,共8页Spectroscopy and Spectral Analysis
基 金:国家自然科学基金项目(22202046)资助。
摘 要:稀土上转换纳米粒子(UCNPs)因其具有毒性小、化学稳定性好和背景荧光低等优点被用于构建荧光纳米传感器。通过溶剂热法制备核壳UCNPs,采用柠檬酸钠对其进行表面配体交换得到水溶性核壳UCNPs(Cit-CS-UCNPs),以Cit-CS-UCNPs作为荧光传感器的能量供体,二氧化锰(MnO_(2))纳米片作为荧光传感器的能量受体,采用荧光共振能量转移(FRET)机理,构建了一种用于食品添加剂二氧化氢(H_(2)O_(2))和叔丁基对苯二酚(TBHQ)检测的荧光纳米传感器(Cit-CS-UCNPs-MnO_(2))。通过扫描电镜(SEM)、荧光光谱和紫外可见吸收光谱(UV-Vis)等分析测试手段对制备的纳米材料的形貌结构和性能进行表征。考察了猝灭剂浓度、孵育温度及孵育时间等实验条件对荧光传感体系检测性能的影响。荧光光谱和UV-Vis实验结果表明,Cit-CS-UCNPs最大发射峰位于654nm,Cit-CS-UCNPs与MnO_(2)结合后,核壳UCNPs发生荧光猝灭,当存在H_(2)O_(2)时,Cit-CS-UCNPs的荧光恢复,说明在此波段H_(2)O_(2)与MnO_(2)纳米片发生氧化还原反应,MnO_(2)纳米片被还原成Mn^(2+),逐渐从Cit-CS-UCNPs的表面解离下来;存在TBHQ时,Cit-CS-UCNPs-MnO_(2)与TBHQ体系峰位与TBHQ偏移到253nm,为TBHQ与MnO_(2)纳米片发生氧化还原反应,使得Cit-CS-UCNPs-MnO_(2)体系中FRET效应减弱,荧光强度回升。SEM结果表明,MnO_(2)纳米片均匀包覆在Cit-CS-UCNPs的周围,在水中仍可保持良好的分散性,表明MnO_(2)纳米片修饰到Cit-CS-UCNPs表面。对猝灭剂高锰酸钾(KMnO4)的浓度进行了优化。结果表明,当KMnO4浓度为10mol·L^(-1)时,猝灭效率可达90%。对检测条件进行优化,结果表明H_(2)O_(2)的检测孵育时间为25min时,MnO_(2)和H_(2)O_(2)之间氧化还原反应基本完全,Cit-CS-UCNPs-MnO_(2)荧光恢复值最大;TBHQ的检测孵育时间为30min。在最佳实验条件下,Cit-CS-UCNPs-MnO_(2)的荧光强度变化比率与H_(2)O_(2)浓度(0~1000μmol·L^(-1))及TBHQ浓度(0~0.6 mmol·L^(-1))分别�Rare earth up-conversion nanoparticles(UCNPs)have been used to construct fluorescent nanosensors because of their low toxicity,good chemical stability,and low background fluorescence.Core-shell UCNPs were prepared using the solvothermal method,and water-soluble core-shell UCNPs(Cit-CS-UCNPs)were obtained by surface ligand exchange with sodium citrate.The Cit-CS-UCNPs were used as the energy donor of the fluorescence sensor,and manganese dioxide(MnO_(2))nanosheets were used as the energy receptor of the fluorescence sensor.Based on the fluorescence resonance energy transfer(FRET)mechanism,a fluorescence nanosensor(Cit-CS-UCNPs-MnO_(2))was constructed for the detection of hydrogen dioxide(H_(2)O_(2))and tertbutylhydroquinone(TBHQ)as food additives.The prepared nanomaterials'morphology,structure,and properties were characterized by scanning electron microscopy(SEM),fluorescence spectrum,and ultraviolet spectrum(UV-vis).The effects of quenching agent concentration,incubation temperature,and incubation time on the detection performance of the fluorescence sensing system were investigated.According to the fluorescence spectra and UV-Vis experimental results,the maximum emission peak of Cit-CS-UCNPs is 654nm.After the combination of Cit-CS-UCNPs and MnO_(2),core-shell UCNPs undergo fluorescence quenching.When H_(2)O_(2)is present,the fluorescence of Cit-CS-UCNPs recovers.The results indicate that H_(2)O_(2)and MnO_(2)nanosheets undergo redox reaction at this band,and MnO_(2)nanosheets are reduced to Mn^(2+),which gradually dissociates from the surface of Cit-CS-UCNPs.In the presence of TBHQ,the peak of the Cit-CS-UCNPs-MnO_(2)and TBHQ system was shifted to 253nm,indicating that the redox reaction occurred between TBHQ and MnO_(2)nanosheets,and the FRET effect was reduced in the Cit-CS-UCNPs-MnO_(2)system,and the fluorescence intensity increased.It can be seen from the SEM results that MnO_(2)nanosheets are uniformly coated around Cit-CS-UCNPs,and maintain good dispersion in water,indicating that MnO_(2)nanosheets are mo
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