Quantum dots encoded white-emitting polymeric superparticles for simultaneous detection of multiple heavy metal ions

Simultaneous detection of multiple heavy metal ions (HMI) is of great importance for the environmental monitoring, and the analytical tools based on multiband emissive fluorescent probes have been regarded as one of the most promising candidate for multiple HMI detection. Herein, the rod-coil amphiphilic block copolymer (BCP) with intrinsic blue fluorescence emission has been synthesized and subsequently employed to encapsulate two types of hydrophobic quantum dots (QD) with green and red fluorescence emission via the three dimensionally confined emulsion self-assembly, leading to the generation of white-emitting superparticles showing good colloidal stability and stable aqueous phase fluorescence. Furthermore, it was found that the fluorescence emission intensity of obtained superparticles can be selectively quenched by Ag+, Hg2+, Cu2+ and Fe3+ ions via different mechanisms, and the four metal ions can be further discriminated according to their distinct combinational quenching effects onto three fluorescent bands of white-emitting superparticles. In addition, an analytical model was built to enable the simultaneous detection of Cu2+, Hg2+ and Fe3+ in the real sample. Basically, the current work opens the new way to fabricate fluorescent probes with multiple emission bands, which can be easily adapted to prepare more complicated QD encoded fluorescent probes for high throughput detection.

多种重金属离子（HMI）的同时检测对环境监测至关重要，基于多波段发射荧光探针的分析工具被视为多种HMI检测最有前景的候选方法之一。在此，合成了具有固有蓝色荧光发射的棒 - 线两亲性嵌段共聚物（BCP），随后通过三维受限乳液自组装将两种具有绿色和红色荧光发射的疏水量子点（QD）包裹起来，从而产生了具有良好胶体稳定性和稳定水相荧光的白色发射超粒子。此外，发现所获得的超粒子的荧光发射强度可通过不同机制被Ag⁺、Hg²⁺、Cu²⁺和Fe³⁺离子选择性猝灭，并且这四种金属离子可根据它们对白色发射超粒子的三个荧光波段的不同组合猝灭效应进一步区分。此外，建立了一个分析模型，以便在实际样品中同时检测Cu²⁺、Hg²⁺和Fe³⁺。基本上，当前的工作开辟了制备具有多个发射波段的荧光探针的新途径，该方法可容易地适用于制备更复杂的量子点编码荧光探针以用于高通量检测。