School of Chemistry & Chemical Engineering, Linyi University, Linyi 276005, China.
ACS Appl Mater Interfaces. 2013 Aug 28;5(16):8146-54. doi: 10.1021/am4022076. Epub 2013 Aug 2.
Molecularly imprinted polymers (MIPs) with trinitrophenol (TNP) as a dummy template molecule capped with CdTe quantum dots (QDs) were prepared using 3-aminopropyltriethoxy silane (APTES) as the functional monomer and tetraethoxysilane (TEOS) as the cross linker through a seed-growth method via a sol-gel process (i.e., DMIP@QDs) for the sensing of 2,4,6-trinitrotoluene (TNT) on the basis of electron-transfer-induced fluorescence quenching. With the presence and increase of TNT in sample solutions, a Meisenheimer complex was formed between TNT and the primary amino groups on the surface of the QDs. The energy of the QDs was transferred to the complex, resulting in the quenching of the QDs and thus decreasing the fluorescence intensity, which allowed the TNT to be sensed optically. DMIP@QDs generated a significantly reduced fluorescent intensity within less than 10 min upon binding TNT. The fluorescence-quenching fractions of the sensor presented a satisfactory linearity with TNT concentrations in the range of 0.8-30 μM, and its limit of detection could reach 0.28 μM. The sensor exhibited distinguished selectivity and a high binding affinity to TNT over its possibly competing molecules of 2,4-dinitrophenol (DNP), 4-nitrophenol (4-NP), phenol, and dinitrotoluene (DNT) because there are more nitro groups in TNT and therefore a stronger electron-withdrawing ability and because it has a high similarity in shape and volume to TNP. The sensor was successfully applied to determine the amount of TNT in soil samples, and the average recoveries of TNT at three spiking levels ranged from 90.3 to 97.8% with relative standard deviations below 5.12%. The results provided an effective way to develop sensors for the rapid recognition and determination of hazardous materials from complex matrices.
以三硝基苯酚（TNP）为虚拟模板分子，CdTe 量子点（QDs）为帽，采用 3-氨丙基三乙氧基硅烷（APTES）为功能单体，四乙氧基硅烷（TEOS）为交联剂，通过种子生长法，在溶胶-凝胶过程中制备了具有三硝基苯酚（TNP）印迹聚合物（MIPs）（即 DMIP@QDs）。基于电子转移诱导荧光猝灭，DMIP@QDs 用于检测基于电子转移诱导荧光猝灭的 2,4,6-三硝基甲苯（TNT）。随着样品溶液中 TNT 的存在和增加，TNT 与 QDs 表面的伯氨基之间形成了 Meisenheimer 配合物。QDs 的能量转移到配合物上，导致 QDs 猝灭，从而降低了荧光强度，从而可以光学检测到 TNT。DMIP@QDs 在与 TNT 结合后不到 10 分钟内产生了显著降低的荧光强度。传感器的荧光猝灭分数在 0.8-30 μM 范围内与 TNT 浓度呈良好线性关系，其检测限可达到 0.28 μM。该传感器对 TNT 表现出明显的选择性和高结合亲和力，对其可能的竞争分子 2,4-二硝基苯酚（DNP）、4-硝基苯酚（4-NP）、苯酚和二硝基甲苯（DNT）具有较高的选择性，因为 TNT 中含有更多的硝基，因此具有更强的吸电子能力，而且因为它与 TNP 在形状和体积上具有高度相似性。该传感器成功应用于测定土壤样品中 TNT 的含量，在三个加标水平下，TNT 的平均回收率在 90.3%至 97.8%之间，相对标准偏差低于 5.12%。结果为从复杂基质中快速识别和测定危险物质提供了一种有效的方法。
