ZnSe quantum dot based ion imprinting technology for fluorescence detecting cadmium and lead ions on a three-dimensional rotary paper-based microfluidic chip

In this study, a newly fluorescent ZnSe quantum dots (QDs) with ion imprinting technology was firstly realized on the three-dimensional (3D) rotary paper–based microfluidic chip platform which can be used to realize specific and multiplexed detection of Cadmium ions (Cd 2+ ) and Lead ions (Pb 2+ ). Compared to CdTe quantum dots, ZnSe quantum dots are less toxic and more environmental friendly. In addition, this design improved the portability of the device by transferred the liquid phase of ZnSe QDs@ion imprinted polymers to solid glass fiber paper. Moreover, the 3D rotary microfluidic chip ( μ PADs) showed great advantages including low cost, simple and fast facile operation, multiplexed detection, and showed good sensitivity and selectivity. Under optimal experiment conditions, our proposed method was enabled to realize specific and multi-channel determination of Cd 2+ and Pb 2+ ions. The developed sensor of Cd 2+ μ PADs provided a linear response from 1 to 70 μg/L with a lower detection limit of 0.245 μg/L, and Pb 2+ μ PADs provided a linear response from 1 to 60 μg/L with a lower detection limit of 0.335 μg/L, respectively. Excitingly, this newly designed 3D rotary μ PADs exhibited quantitative information conveniently, which showed the promising application prospects to rapid testing target metal ions in environmental in the future.