鉴于长余辉材料免实时激发特性可有效消除激发光源及复杂样品自体荧光的干扰, 近红外长余辉材料在生物成像领域受到了广泛关注。但其在荧光传感应用方面的报道相对较少, 尤其是利用长余辉纳米粒子来检测金属阳离子鲜有报道。本文采用水热法制备了Sn4+共掺的近红外长余辉纳米材料ZnGa2O4∶Cr3+,Sn4+ (ZGSC), 再以包硅处理得到在水溶液中分散性良好的荧光探针ZnGa2O4∶Cr3+,Sn4+@SiO2(ZGSC@SiO2)。基于Fe3+对长余辉材料ZGSC@SiO2的荧光猝灭效应, 构建了一种选择性好、无背景干扰的近红外长余辉荧光探针ZGSC@SiO2, 用于Fe3+的定量检测。采用时间分辨光谱可有效地消除背景干扰, 实现了高信噪比检测, 其线性范围为50~800 μmol/L, 检出限为25.12 μmol/L。选取了3种补铁口服液作为实际样品, 对其总铁含量以及Fe3+的含量进行检测, 并进行了加标实验。实验结果表明, 测定结果中总铁含量与标示值吻合; 3种样品中总铁含量的加标回收率为99.00%~99.79%, 相对标准偏差(RSD)为2.416%~3.808%; Fe3+含量的加标回收率为99.90%~102.69%, RSD为3.263%~4.296%, 满足测定要求。根据样品中总铁含量和Fe3+含量, 可计算得出Fe2+含量, 因此该荧光传感体系具有可同时检测Fe3+与Fe2+的优点, 可以用于补铁口服液中有效价态Fe2+的质量控制检测。

Since persistent luminescent materials are free from real time excitation, which can effectively eliminate the interference of excitation light source and auto-fluorescence from complex sample, near infrared persistent luminescent materials attract wide attentions in the field of biological imaging. However, there are relatively few reports on its application in fluorescence sensing, especially in metal cations detection. The near-infrared persistent luminescent nanophosphor ZnGa2O4∶Cr3+,Sn4+ (ZGSC) was synthesized by hydrothermal method, and worked as fluorescent probe after coating with silicon ZnGa2O4∶Cr3+,Sn4+@SiO2 (ZGSC@SiO2), which is well dispersed in an aqueous solution. Based on the phenomenon that the fluorescence of ZGSC@SiO2 can be quenched by Fe3+, a fluorescence sensing method with good selectivity and interference free was established for detecting Fe3+. The background interference can be effectively eliminated by using time-resolved spectrum, and high signal-to-noise ratio detection can be realized. The detection linear range is 50-800 μmol/L, and the detection limit is 25.12 μmol/L. Three kinds of iron supplement oral liquid were selected as the real samples, and the content of total iron and Fe3+ were detected. The results show that the total iron contents in the three samples are matched well with the contents claimed in the labels. The average recoveries of total iron content in the three samples were 99.00%-99.79%, and the average recoveries of Fe3+ content were 99.90%-102.69%. The RSDs of the total iron content are 2.416%-3.808% and the RSDs of the Fe3+ content are 3.263%-4.296%, respectively. The Fe2+ content can be obtained by subtracting Fe3+ content from the total iron content in the sample. Therefore, the fluorescence sensing system can simultaneously detect Fe3+ and Fe2+, and can be used for quality control of the effective valence state Fe2+ in iron supplement oral liquid.