This Small Business Innovation Research (SBIR) Phase II project is designed to develop a nonintrusive diode laser sensor for detecting oxygen in the headspace of pharmaceutical vials. Many drugs are oxygen sensitive and must be bottled in an oxygen free environment. There are no nonintrusive<br/>methods available to measure residual oxygen levels in sealed product vials. A nonintrusive sensor would generate large cost savings for pharmaceutical manufacturers. During the Phase II project, a prototype off-line instrument will be constructed. This instrument will be tested at pharmaceutical manufacturing facilities. In addition if time permits, on-line experimental measurements will be performed.<br/><br/>In addition to being useful for the pharmaceutical industry, this technology will be extendable to a variety of packaged products in other industries. These industries include the food, alcoholic beverage, and medical instrument markets. This technology can also be used to detect<br/>other species in packaged products such as water vapor or carbon dioxide.