Integrated microfluidic gas sensor for detection of volatile organic compounds in water

A polymer microfluidic system for monitoring of volatile organic compounds diluted in water is presented. The sensor platform employs silicon-based microhotplate gas sensors as active detection elements, using a silicon-in-plastic microfabrication technology to enable integration of individual sensor chips into a larger polymer microfluidic substrate. The fabrication process provides seamless fluidic and electrical interconnects between the silicon and polymer substrates. The chemical monitoring system is designed to sample a water source, extract solvent present within the aqueous sample into the vapor phase, and direct the solvent vapor past the integrated gas sensor for analysis. Design, fabrication, and characterization of a prototype system is described, and results from illustrative measurements performed using methanol, toluene, and 1,2-dichloroethane in water are presented.