The ability to identify heavy metal contamination in a variety of water sources, quickly and inexpensively, would greatly help in many situations. Many pollution problems could be mitigated if an easy, in-situ analytical method existed to indicate the presence of contaminated water.
Currently, the state of the art technique for metal detection in water is inductively coupled plasma-mass spectrometry – a laboratory centric method.
Navy researchers have developed a simple, easily scaled process for producing fluorescent nanoparticles, including quantum dots that are relatively non-toxic and environmentally stable in both air and water. These nanoparticles are made from more benign metals such as zinc, silver, indium, and copper. The interaction between the nanoparticles and a target analyte (particularly metal ions, both cations, and anions) are used for sensing applications and they are ideally suited for testing in a non-laboratory environment. The technology encompasses several methods of detection including shifting of the wavelength of fluorescence, an enhancement of fluorescence, or quenching of fluorescence when a specific target element or molecule is present.
Analytes of environmental interest such as Cu2+, Hg2+, and Cr6+ have been detected in concentrations as low as ~1ppm.
- Non-toxic, air, and water stable
- Can be used as the basis for a fast, simple, visual detection system without the need for expensive analytical instrumentation or pretreatment of samples
- Can be used for the detection of multiple target analytes using a single test element
- Selective fluorescence enables an instant-read visual test to detect in real time the contamination of metal ions
- Contained in the patent is a simple, four step process for nanoparticle synthesis and functionalization allowing for scale-up
- US patents 10,107,787 and 10,125,311 available for license
- Several formulations have been made and tested