基于MgAl-8-HQ LDH复合粒子选择性检测Fe^(3+)的荧光传感器

A Fluorescent Chemical Sensor Based on MgAl-8-HQ LDH Composite Particle for the Selective Detection of Fe^(3+)

为实现对Fe^(3+)高选择和简便检测,基于镁铝层状双氢氧化物(MgAl LDH)层板的Al^(3+)的可调控性及易与8-羟基喹啉(8-HQ)发生配位作用,设计制备了8-HQ插层配位的高荧光性8-羟基喹啉镁铝层状双氢氧化物(Mg_xAl-8-HQ LDH),同时采用IR,XRD,UV-Vis及分子荧光光谱仪表征其结构和性能。IR分析表明8-HQ与铝离子生成C-O-Al和C-N-Al配位键;XRD揭示8-HQ插入MgAl LDH的层板间,致(003)衍射峰向2θ低角度方向移动,衍射峰强度随Mg与Al摩尔比增加而增强;因MgAl LDH层间的8-HQ与Al^(3+)配位,致8-HQ在314 nm处的吸收峰消失,同时在376 nm处出现了金属离子与配体之间的跃迁吸收峰;荧光分析表明:Mg_xAl-8-HQ LDH的荧光强度随Al^(3+)含量降低而增强,当镁铝离子物质的量之比为4∶1时,荧光强度显著强于8-羟基喹啉铝。通过研究金属离子对Mg_4Al-8-HQ LDH粒子荧光光谱的影响,发现该粒子对金属离子表现出显著的选择和差异性,尤其对Fe^(3+)具有高选择性。进一步研究[Fe^(3+)]对Mg_4Al-8-HQ LDH粒子的溶液颜色及荧光强度的影响表明:在10^(-6)~10^(-2)mol·L^(-1)内随[Fe^(3+)]增加,Mg_4Al-8-HQ LDH粒子溶液的颜色由浅黄色变成墨绿色,故可实现上述浓度范围内Fe^(3+)的比色传感;同时其荧光强度显著降低,当[Fe^(3+)]为10^(-3)mol·L^(-1)可完全猝灭其荧光,当-log[Fe^(3+)]为3~6时,-log[Fe^(3+)]与溶液荧光强度呈负相关函数关系,可实现对Fe^(3+)的高选择和灵敏性荧光传感检测,据此本实验成功建立了Mg_A Al-8-HQ LDH粒子荧光和比色双重传感检测Fe^(3+)的新方法。

In order to achieve the highly selective and Simple detection for ferric ion,strong-fluorescent 8-hydroxyquinoline（8-HQ）Mg-Al layered double hydroxide（MgχAl-8-HQ LDH）was designed and prepared by 8-HQ’s intercalation and ready coor-dination based on adjustment of Al3 ＋ on Mg-Al layered double hydroxides（MgAl LDH）laminates.Meanwhile its structure and property were characterized by IR,XRD,UV-Vis and fluorescent spectrometer.IR analysis showed coordinate bonds of C—O—Al and C—N—Al between 8-HQ and Al3 ＋ were generated.XRD revealed that 8-HQ had already inserted in MgAl LDH lami-nates,and it made （003）diffraction peaks move to low 2θangle direction,and the diffraction peak intensity was enhanced with the molar ratio of Mg and Al increasing.Because the coordination reaction between 8-HQ and Al3 ＋ in MgAl LDH laminates took place,it induced the absorption peak of 8-HQ at 314 nm disappeared,at the same time the transition absorption peak at 376 nm between metal ions and ligands appeared.As demonstrated by fluorescence spectroscopic analysis,fluorescence intensity of MgχAl-8-HQ LDH increased with the content of Al3 ＋ reducing,when the molar ratio of Magnesium and Aluminium ion is 4∶1, its fluorescence intensity enhanced more significantly than 8-hydroxyquinoline aluminum.Through the research on the influence of metal ions on the fluorescence spectra of Mg4 Al-8-HQ LDH particle,it was found that the particle to metal ions exhibited sig-nificant selection and difference,especially with high selectivity for Fe3 ＋ ion.The effect of [Fe3 ＋ ]on the color and fluorescence intensity of Mg4 Al-8-HQ LDH particle solution was further studied,and the results showed that the solution varied from light yellow to dark green with the content of Fe3 ＋ in 10 -6 to 10 -2 mol·L-1 increasing,so it can implement colorimetric sensing for Fe3 ＋ in the above range.And at the same time its fluorescence intensity significantly decreased,and its fluorescence could be completely quenched,when [Fe3 ＋ ]was 10 -3 mol·L-1 .When-log[Fe3 ＋ ]was in 3 to 6,negative correlation function appeared between-log[Fe3 ＋ ]and its fluorescence intensity,so it could implement fluorescence sensing detection for Fe3 ＋ with high selec-tivity and sensitivity.According to the above research results,a new method of fluorescent and colorimetric dual sensor detection of Fe3 ＋ by Mg4 Al-8-HQ LDH particle was successfully established.