基于 MgAl-8-HQ LDH 复合粒子选择性检测 Fe3＋的荧光传感器

摘要

为实现对 Fe3+高选择和简便检测，基于镁铝层状双氢氧化物（MgAl LDH）层板的 Al3+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（MgχAl-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 Al3+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：MgχAl-8-HQ LDH 的荧光强度随 Al3+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 Mg4 Al-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 Fe3+具有高选择性。进一步研究[Fe3+]对 Mg4 Al-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[Fe3+]增加， Mg4 Al-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 Fe3+的比色传感；同时其荧光强度显著降低，当[Fe3+]为10－3 mol·L－1可完全猝灭其荧光，当-log[Fe3+]为3～6时，-log[Fe3+]与溶液荧光强度呈负相关函数关系，可实现对 Fe3+的高选择和灵敏性荧光传感检测，据此本实验成功建立了 Mg4 Al-8-HQ LDH 粒子荧光和比色双重传感检测 Fe3+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.