Chemiluminescent chemical sensors for inorganic and organic vapors

A novel class of chemiluminescent, chemical sensors are described which are based upon the immobilization of a chemiluminescent reagent, luminol or tris(2,2'-bipyridyl)ruthenium(III) (Ru(bpy)(3)(3+)), between a miniature photomultiplier tube and a teflon diffusion membrane. The membrane serves to separate the chemiluminescent matrix from a sampled stream of air. Luminol was immobilized within a hydrogel support matrix and utilized for the detection of ppm levels of chlorinated hydrocarbons, including CCl4(g), CHCl3(g) and CH2Cl2(g). This was achieved via the incorporation of a heated Pt filament into the inlet line as a pre-oxidative step prior to passage of the gas stream across the teflon membrane. In an alternate approach, the organometallic complex, Ru(bpy)(3)(3+), an electrochemically regenerable chemiluminescent reagent, was investigated as a reagent for monitoring trace levels of strongly reducing vapors such as hydrazine or ammonia vapor. This approach has been developed into a prototype, real-time instrument. We report the initial testing of a hand-held instrument which is similar to the cell utilized for the luminol chemiluminescence, with the exception that a three electrode electrochemical cell has been incorporated into the system for continuously regenerating the chemiluminescent reagent, Ru(bpy)(3)(3+).