Several years ago manganese beside other trace metals was found to be a minor constituent of cigarette smoke and ash [1]. An E.P.R. study [2] confirmed the presence of Mn 2+ ions in cigarette smoke. They observed a weak sixline spectrum superimposed by a strong signal of an unidentified radical (g = 2.0023). No information was given concerning the origin or chemical surroundings of manganese in cigarettes.
Fig. 1. a) E. P. R. spectrum of a whole cigarette (dried at 100 oC for 10 h). Microwave frequency f=9.58 Gc, microwave power P=17 mW, spectrometer gain G=1.6 x 10^5, sweep width 700 gauss, sweep time 20 min. b) E.P.R. spectrum of cigarette tobacco. Spectrometer settings unchanged. c) E.P.R. spectrum of cigarette paper (folded). G=1.25 x 10^5
We therefore investigated whole cigarettes, and separately their tobacco and paper in an x-band spectrometer (Bruker ER 200 D) at ambient temperatures. For eight of ten popular brands we obtained similar spectra (Fig. 1) but different from those in [2]. The spectrum of tobacco and the whole cigarettes (Fig. I a, I b) consists of a multiline signal superimposed by a broad resonance of unknown origin, where as the spectrum of cigarette paper (Fig. I c) is identical with that of ordinary
Fig. 2. a) E.P.R. spectrum of calcite powder(p.a. grade from E.Merck). f=9.77 Gc, P=1.7 mW, G=3.2 x 10^4. b) E.P.R. spectrum ofordinary white paper. G=8 x 10^4
white paper (Fig. 2 b). Shape and linewidth of the latter differ only slightly from those of a sample of CaCO, powder (p.a. grade from E. Merck; contains Mn2 + as impurity) depicted in Fig. 2a. A similar E.P.R. spectrum of CaCO3: Mn (0.06 weight%) powder was published by Hurd et al. [3]. They interpreted the powder spectrum as a superposition of 30 transitions with strong orientation dependence, which are observed in single crystals of natural calcite (see [4,5] for further information about E.P.R of manganese in calcite single crystals).
Both linewidth and resonance field of these transitions in calcite single crystals depend on strains or defects of the lattice and models explaining these dependencies have been given [5]. The small crystallites of calcite powder are strained in the milling process [6]. Thus the differences between Fig. 2a and 2b can be accounted for byeffects of strain and defects.
The E.P.R. spectra indicate that manganese ion in cigarettes originates from manganese-containing calcite powder which is.used as an additive in the manufacture process of paper [7] as well as of tobacco [8].
Received December 9, 1981