Large-scale fractionation of cigarette smoke condensate for chemical and biologic investigations.

Most of the tumorigenicity of CSC for animals can be con centrated in the neutral and acidic fractions. In an early study (19), roughly quantitative results showed that, although the major tumor-initiating activity was concentrated in the carbon tetrachloride eluate from silicic acid chromatography of the neutrals, some activity was found in the hexane eluate from this column, and additional activity occurred in the acidic, basic, and dichloromethane-insoluble fractions. Most of the activity was lost when the carbon tetrachlonde eluate was re moved and all the other fractions were recombined. In another publication, the major tumor-initiating activity was found cx clusively in hexane eluates from silicic acid columns (17). In further work (16) it was shown that the processes of fraction ating and recombining did not result in a loss of activity, since a reconstituted condensate prepared by recombining the sepa rated acidic, basic, and neutral fractions was as active as the original condensate. However, subsequent findings indicated that these results could not be confirmed, and some loss on recombination was evident (17). Recently, a more precise de termination showed that a neutral fraction (prepared sepa rately from fresh CSC) had about 80% as much tumorigenicity for mouse skin as thoroughly dried and stored condensate (3). The relative contribution of the traces of carcinogenic PAH presumably present in the neutral fraction was not deter mined, nor was there any attempt at a direct comparison with a neutral fraction actually isolated from the stored condensate. On the other hand, in the same study a fresh whole CSC which was not dried was twice as active as the same neutral fraction. The substances responsible for the additional tumorigenicity for mouse skin of the fresh versus stored condensate were not identified. All of the studies published to date suffer from several dis advantages. In all cases, fractionation has been relatively super ficial. With one possible exception in which unpublished find ings were summarized (17), the recently isolated brown pig ments of CSC (4—6, 14) have not been separated and tested biologically. In no case have the precise details of fractionation been described. Also, in no instance has the variability of yields obtained in the fractionation been revealed. The present study is the first stage of a large-scale joint effort to overcome these disadvantages. The present report describes details of the fractionation of CSC, including the variability of yields over a period of 12 months. During this time, a concurrent chemical study of the composition of se lected fractions has been underway, and a number of prey SUMMARY