Spin Trapping of Radicals in Gas-Phase Cigarette Smoke

Since the spin trapping technique was developed and utilized to determine radicals in the gas phase (see reviews [1—3]), it has become attractive as a method of detecting radicals in gas-phase tobacco smoke. A first study of this sort was reported by Bluhm et al. in 1971 [4], while previous studies were forced to rely on the measurements of smoke condensate at liquid nitrogen temperature [5, 6]. Menzel et al. [7] estimated the concentration of spin-trapped radicals in smoke, but the principal aim of this paper was to explore the utility of the dipolar broadening of ESR lines for quantification rather than to assign a structure of the trapped radicals. The laboratory of W. A. Pryor is presently the only research group carrying out systematic studies of radicals in tobacco smoke by spin trapping [8—11]. We decided to publish our own results at this stage which, in the main, present an independent confirmation of those by Pryor et al., and in certain respects offer new evidence.