Electron-spin resonance study of mainstream and sidestream cigarette smoke: nature of the free radicals in gas-phase smoke and in cigarette tar.
Electron-spin resonance study of mainstream and sidestream cigarette smoke: nature of the free radicals in gas-phase smoke and in cigarette tar.
复制标题
DOI：
10.1289/ehp.8347345
复制
发表时间：
1983-01
影响因子：
10.4
通讯作者：
Church DF
中科院分区：
文献类型：
--
作者：
Pryor WA;Prier DG;Church DF
以α-苯基-N-叔丁基硝酮(PBN)为自旋陷阱，用电子自旋共振ESR自旋捕获技术研究了主流卷烟和侧流卷烟烟气气相中的自由基。我们捕获的主要自由基似乎是烷氧基。主流和侧流气相烟雾各自具有大致相同的自由基浓度，每支香烟大约有1×10(16)个自由基(或每根烟5×10(14)个自由基)。这些自由基是反应性的，但它们的寿命似乎非常长：超过5分钟后，它们仍然被气相烟雾自旋捕获。我们认为，在气相香烟烟雾中存在一个稳态浓度的活性自由基。我们认为，这种稳定状态是由于一氧化氮(以高浓度的形式存在于烟雾中，相对不活跃)缓慢氧化成更具活性的二氧化氮，然后二氧化氮与烟雾中的活性有机分子(如烯烃和二烯烃)发生反应。这里报告的初步实验支持这一假设。来自主流和侧流烟雾的焦油含有持久的自由基，表现出宽广的单线电子自旋共振光谱，g值为2.003。焦油自由基可以提取到叔丁基苯和其他有机溶剂中，我们已经对这些溶液应用了各种分馏程序。大多数自由基出现在含有酚类烟叶色素的部分中。用碱处理焦油的酒精溶液会产生一组新的自由基，这些自由基似乎是由于焦油中的酚类和多酚类物质的氧化而产生的半醌类自由基。
Radicals in the gas phase of both mainstream and sidestream cigarette smoke have been studied using electron-spin resonance ESR spin-trapping techniques with alpha-phenyl-N-tert-butyl nitrone (PBN) as the spin trap. The principal radicals we trap appear to be alkoxyl radicals. Mainstream and sidestream gas-phase smoke each have about the same concentration of radicals, about 1 X 10(16) radicals per cigarette (or 5 X 10(14) per puff). These radicals are reactive, yet they appear to be remarkably long-lived: they are still spin trapped from gas-phase smoke after more than 5 min. We propose that a steady-state concentration of reactive radicals exists in gas phase cigarette smoke. We suggest that this steady state is produced by the slow oxidation of nitric oxide (present in high concentrations in smoke and relatively unreactive) to the more reactive nitrogen dioxide, followed by the reaction of nitrogen dioxide with reactive organic molecules in smoke (such as olefins and dienes). Preliminary experiments reported here support this hypothesis. Tar from both mainstream and sidestream smoke contains persistent free radicals that exhibit broad, single-line ESR spectra with g values of 2.003. The tar radical can be extracted into tert-butylbenzene and other organic solvents, and we have applied a variety of fractionation procedures to these solutions. Most of the radicals occur in the fractions that contain the phenolic tobacco leaf pigments. Treatment of alcoholic solutions of tar with base generates a new group of radicals that appear to be semiquinone radicals derived from the oxidation of the phenolic and polyphenolic species in tar.