Core-Shell Quantum Dot-Based Honeycomb Films on Capillary Walls for Rapid In Situ Ascorbic Acid Detection

The rapid, portable, and in situmeasurement of the ascorbic acid(AA) solution remains a challenge, and there is no suitable way toachieve multiscale regulation of the measurement range and sensitivity.In this work, water-soluble CdTe, CdTe/CdSe, and CdTe/CdSe/ZnS quantumdots (QDs) were used as fluorescence probes (FPs), and the specificsensitivity of photoluminescence (PL) intensity and AA were used asa detection indicator. By changing the concentration of the FP andthe type of core-shell structure, multiscale regulation ofthe measurement range and sensitivity was realized. The same FP withdistinct sensitivity in different measurement ranges is ingeniouslyrealized by double-layer core-shell CdTe/CdSe/ZnS with typeII-I band gap transition, which greatly expanded the application fields.The maximum measurement range was 0-27 & mu;M and the minimumdetection limit was 0.014 & mu;M for three FP systems. The capillarysensor with a honeycomb QD film attached to the inner wall was preparedby drying at room temperature, high-temperature heating, and laserprocessing, which greatly increased the contact area between the QDsand AA and reduced the measurement time. Furthermore, the microfluidicsystem was used to precisely control the deposition area and positionof the film, the concentration of the FP was adjusted and the depositionstatus of the film was observed in real time, so as to achieve real-timein situ rapid detection of the four concentration orders of the AAsolution. This work is of great significance for the rapid, portable,multifield, and in situ real-time detection in the field of biomoleculedetection.