Individuals needing or wanting to examine lead content in their drinking water on-demand and in virtually any environmental setting.
The discovery of lead in drinking water in Flint, MI drew renewed attention to the health risks posed by the metal. This inexpensive system uses a smartphone and a lens made with an inkjet printer that can detect lead in tap water at levels commonly accepted as dangerous. The system is portable and easy to operate, as well as able to detect lead concentrations at 5 parts per billion in tap water. The system combines nano-colorimetry with dark-field microscopy integrated into a smartphone microscope platform. The self-contained microscope — which can operate in both fluorescence and dark-field imaging modes — was paired with an inexpensive Lumina 640 smartphone with an 8-megapixel camera. To test the system, tap water was spiked with varying amounts of lead, ranging from 1.37 parts per billion to 175 parts per billion. Chromate ions react with the lead to form lead chromate nanoparticles; the nanoparticles can be detected by combining colorimetric analysis and microscopy. The analysis measured the intensity detected from the nanoparticles, correlating that to the lead concentration, and verified that the reaction was spurred by the presence of lead.
University of Houston, Texas
The researchers are building upon the smartphone microscope platform to create a consumer product.
Even small amounts of lead can cause serious health problems, with young children especially vulnerable to neurological damage. EPA standards require lead levels in drinking water to be below 15 parts per billion, and currently available consumer test kits are not sensitive enough to accurately detect lead at that level.