This Small Business Innovative Research Phase I project addresses an immediate need for a real-time means of endpoint monitoring solvent drying processes in pharmaceutical manufacturing. The specific innovation is the combination of a novel, broadly tunable, mid-infrared diode laser source with ultra-sensitive absorption techniques, to provide a non-contact means for sensing trace organic solvent vapor concentrations in fluidized bed dryers and spray coaters. The probe laser source utilizes Difference Frequency Generation (DFG) to convert visible and near-infrared laser light to the mid-infrared. Its ability to continuously tune over 200 cm-1 enables the measurement of organic vapors having broad, infrared absorption bands near 3.5 microns. The Phase I objectives are to use the DFG source to measure organic solvent vapors, determine analyzer detection limits, and create a preliminary design for an industrial sensor. The Phase I program will verify the technical and commercial feasibility of the mid-infrared solvent monitor. <br/><br/>The proposed solvent drying endpoint monitors will provide the pharmaceutical industry with real-time data enabling improved drug manufacturing process efficiency and quality. The sensors may eliminate the need for off-line residual solvent analysis that often halts processing and holds completed product for release. There are numerous applications for the technology, including environmental monitoring of organic pollutants, industrial HVAC controls, breath analysis, hospital air and gas quality control and sensors to screen for alcohol and other toxics.