The two forms of the reagent (aqueous and anhydrous) yielded vastly different results. The aqueous reagent produced slow, low-intensity chemiluminescence; and the anhydrous reagent generated a fast, bright response in the presence of 3,6-diacetylmorphine (heroin). The disadvantage of the anhydrous reagent is the use of a flammable solvent sprayed as an aerosol, so no naked flame can be present when using this reagent. The aqueous reagent was selective for 3,6-diacetylmorphine over codeine, acetylcodeine, and noscapine, but 3-monoacetlymorphine also gave slow long-lasting chemiluminescence with the aqueous reagent. This should not be a problem, however, since 3-monoacetylmorphine is a byproduct in the synthesis of heroin. The chemiluminescence reaction was studied by using stopped-flow instrumentation in order to gain insight into the reaction kinetics of 3,6-diacetylmorphine and the tris(2,2'-bipyridyl) ruthenium (III) reagent in an aqueous and anhydrous environment, as well as in the presence of some heroin cutting agents. The reagent was dispensed as a spray over suspect articles. Several surfaces were examined, including polymer bank notes and the laboratory bench. 1 table, 2 figures, and 26 references