Portable Quantum Dot Measurement System

Summary

Detecting heavy metals in water is essential to ensure clean drinking water and appropriate regulatory decisions following an accident (e.g., a spill) or an emergency. Traditionally, high-sensitivity detection of heavy metals requires bulky and costly (to purchase and operate) lab-based instruments. We propose developing a palm-sized, element-specific, highly-sensitive, battery-operated, smartphone-controlled system for on-site measurement to provide timely heavy metal concentration information. Two-dimensional quantum dots (2D-QDs) will be modified by adding molecular components specific to a heavy metal of interest; the interaction between the heavy metal and the chosen molecular component will result in visible fluorescence that can be measured. A high-sensitivity instrument will be developed around a battery-operated, portable microplasma, which will serve as a light source, and a battery-operated photo-detector. For measurement, modified 2D-QDs will be added to a contaminated water sample inside a cuvette placed in the instrument. When excited by the light emitted by the microplasma, the resultant fluorescence will indicate the presence and concentration of heavy metals in the water sample. Further, data acquisition electronics will be embedded in the instrument and a smartphone can be used to receive the digital data wirelessly. The development of this sensor can significantly improve the monitoring of heavy metals in waters in Canada and worldwide.

Figure 1. (Left) A concept diagram of the proposed instrumentation consisting of the light source, a cuvette with a water sample and a detector. (Right) The proposed fluorescence-measurement system will be palm-sized, battery operated and controlled by a smartphone.