The long term goal of the proposed project is to create method and instrumentation with which to measure, the concentration of S-nitrosothiol compounds rapidly and with a sensitivity capable of detecting these species in the biologically relevant range. S-nitrosothiols have a broad range of biological functions some best explained by the compounds acting as nitric oxide (NO) donors and others through other molecular mechanisms. These compounds are important because they constitute a significant endogenous biological store of NO. Measurement of S-nitrosothiols will be effected by accurate measurement of NO released by controlled decomposition of these compounds. The important and diverse interactions of NO with free radicals are now well known in the health sciences. The proposed project will innovate new state of the art NO sensors so as to offer detection of S- nitrosothiols at concentrations of 1 nanomolar or less in blood and plasma. If successful, it is anticipated the projected instrumentation will be readily accepted by researchers worldwide. PROPOSED COMMERCIAL APPLICATIONS: It is expected that with the great and continued interest from the bioscience research community in the physiological and pathophysiological role of NO; a role for the measurement of thionitrites in medical diagnosis and treatment will emerge very soon. This would ultimately assure the commercial success of this undertaking.