Mainstream tobacco smoke is a complex and dynamic aerosol, consisting of particulate and vapour phases. Most approaches to determine mainstream smoke toxicant yields are based on offline techniques that limit the opportunity to observe in real time the processes leading to smoke formation. The recent development of online real-time analytical methods offers many advantages over traditional techniques. Here we report the LM2X-TOFMS (Borgwaldt GmbH, Germany), a commercial instrument that couples a linear smoking engine with a time-of-flight mass spectrometer for real-time per-puff measurement of the vapour phase of mainstream cigarette smoke. Total cigarette and puff-by-puff (μg/puff) yields were evaluated, in line with International Council of Harmonisation recommendations, for seven smoke toxicants: acetaldehyde, acetone, 1,3-butadiene, 2-butanone, benzene, isoprene and toluene. Measurements were unaffected by small system changes including replacing the sampling capillary or time of day (all P > 0.05), indicating that the LM2X-TOFMS is rugged. Control charts showed that the system has good stability and control. Analysis of certified gas mixtures of six concentrations of each analyte showed a highly linear response for all seven analytes (R2 = 0.9922-0.9999). In terms of repeatability, the lowest variation was observed for isoprene with a coefficient of variation (CV) of < 6% for each concentration. Acetaldehyde showed the highest CV, increasing from 8.0 to 26.6% with decreasing gas concentration. Accuracy was analysed in terms of relative error, which was ± 16% for six of the analytes; however, the relative error for acetaldehyde was (- 36.2%), probably due to its low ionisation efficiency under the instrument's vacuum ultraviolet lamp. Three cigarette products (reference and commercial) with different ISO tar levels were analysed by the LM2X-TOFMS puff by puff under ISO regulatory smoking conditions. The relative standard deviation based on average yield per cigarette for each analyte in each product (summed puffs per product, n = 30) ranged from ≤ 9.3 to ≤ 16.2%. Measurements were consistent with published data per cigarette. In conclusion, the LM2X-TOFMS is suitable for determining the vapour-phase yields of seven analytes on a real-time, puff-by-puff basis, and can be utilised for both fast screening (qualitative) and quantitative measurements of mainstream cigarette smoke.

中文翻译：

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对用于主流烟草烟雾分析的在线实时软光子电离飞行时间质谱仪进行评估。

主流烟草烟雾是一种复杂且动态的气溶胶，由颗粒相和蒸气相组成。大多数确定主流烟雾毒物产量的方法都是基于离线技术，这限制了实时观察导致烟雾形成的过程的机会。最近发展的在线实时分析方法比传统技术具有许多优势。在此，我们报告 LM2X-TOFMS（Borgwaldt GmbH，德国），这是一种商用仪器，将线性吸烟引擎与飞行时间质谱仪结合在一起，用于实时测量每次抽吸时主流卷烟烟雾的气相。根据国际协调委员会的建议，对卷烟和逐口吸烟（μg/一口）的总产量进行了评估，评估了七种烟雾毒物：乙醛、丙酮、1,3-丁二烯、2-丁酮、苯、异戊二烯和甲苯。测量结果不受小的系统变化的影响，包括更换采样毛细管或一天中的时间（所有 P > 0.05），表明 LM2X-TOFMS 坚固耐用。控制图表明系统具有良好的稳定性和控制性。对每种分析物六种浓度的认证气体混合物的分析显示，所有七种分析物均呈现高度线性响应 (R2 = 0.9922-0.9999)。就重复性而言，观察到异戊二烯的变异最小，每个浓度的变异系数 (CV) < 6%。乙醛表现出最高的 CV，随着气体浓度的降低从 8.0% 增加到 26.6%。准确度按照相对误差进行分析，六种分析物的相对误差为 ± 16%；然而，乙醛的相​​对误差为(- 36.2%)，可能是由于其在仪器真空紫外灯下的电离效率较低。在 ISO 监管吸烟条件下，通过 LM2X-TOFMS 逐口分析具有不同 ISO 焦油含量的三种卷烟产品（参考和商业）。基于每种产品中每种分析物每支香烟的平均产量（每种产品的抽吸次数总计，n = 30）的相对标准偏差范围为 ≤ 9.3 至 ≤ 16.2%。测量结果与每支香烟公布的数据一致。总之，LM2X-TOFMS 适合逐口实时测定七种分析物的气相产率，并且可用于主流卷烟烟雾的快速筛查（定性）和定量测量。