The release of hazardous chemical vapors has the potential for severe casualties, and the detection of such chemicals is therefore critically important for homeland security. Despite this threat, there exists no commercially available, portable gas detection product that can quickly and cost-effectively sense most hazardous gases. In this Phase I project, we will develop a new generation of stable chemisorptive sensor materials that are highly sensitive towards reactive small molecule gases and that can withstand repeated exposures to multiple reactive gases. In addition, we will design and demonstrate methods for improving drift stability through development of sensor fabrication techniques and through the application of new drift-compensation algorithms. The technology builds on previous DHS-sponsored work in which the company demonstrated an initial prototype hand-held chemical detection system. In a continuing Phase II effort, we will validate an integrated detection system that incorporates the new sensors and drift-correction features into a next-generation prototype using simple, low-cost digital readout electronics. The outcome of this effort will be a detector based on microchemical sensor arrays that can be used to quickly and effectively detect the presence of hazardous chemical vapors.