Spectroscopic Detection of Water Contaminants Using Glow Discharges from Liquid Microelectrodes

Background: Threats to drinking water supplies from industrial and biochemical pollutants have created the need for rapid on-site tools that detect and analyze trace contaminants in water. Current protocols for assessing water quality typically require transport of water samples to a laboratory for analysis with a plasma spectrometer. In plasma spectroscopy a water sample is sprayed into a high-frequency RF inductively-coupled plasma. Vaporized water droplets are then spectrally analyzed to determine the composition and quantity of impurities such as heavy metals.Technology Description:UW-Madison researchers have developed a micro-fabricated on-chip spectroscopic system for on-site real-time analysis of trace contaminants in liquids and gases. The system works as follows: Two microfluidic channels transport sampled water from two large reservoirs into two smaller pools or liquid electrodes. A micro-glow discharge generated between the liquid electrodes sputters water molecules and impurity atoms into the discharge region. The resulting discharge emits discrete wavelengths of light that correspond to specific atomic transitions. By analyzing a spectrum of these wavelengths the chemical composition of the water can be determined.Applications:1) Water impurity analysis2) Gas detection for military applications3) Localized detection of automobile emissions 4) Wastewater analysis for compliance with environmental regulationsPatent Status:US6686998Opportunity for collaboration:The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing a system for on-site real-time analysis of trace contaminants in liquids and gases.