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Mg4Al-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Mg4Al-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, Mg4Al-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Mg4Al-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 coordination 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 laminates, and it made (003) diffraction peaks move to low 2θ angle 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 Mg4Al-8-HQ LDH particle, it was found that the particle to metal ions exhibited significant selection and difference, especially with high selectivity for Fe3+ ion. The effect of［Fe3+］ on the color and fluorescence intensity of Mg4Al-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 selectivity and sensitivity. According to the above research results, a new method of fluorescent and colorimetric dual sensor detection of Fe3+ by Mg4Al-8-HQ LDH particle was successfully established.