Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
Environ Sci Technol. 2020 Nov 17;54(22):14372-14379. doi: 10.1021/acs.est.0c04163. Epub 2020 Nov 6.
Organic films on indoor surfaces are ubiquitous, but details about their composition and growth over timescales less than a month are not fully understood. To address these gaps in understanding, organic film samples in an apartment unit were collected over the course of 17 days using passive samplers and analyzed in a non-targeted manner using direct analysis in real-time mass spectrometry (DART-MS). Overall, the chemical composition observed across various locations within the apartment are very similar. Mass spectra also show clear evidence for the growth of semi-volatile compounds from natural sources and consumer products, such as carboxylic acids and plasticizers. Certain compounds show evidence for equilibration, mostly consistent with surface partitioning models based on octanol-air partition coefficients (). Compounds which have higher molecular weight or larger values tend to equilibrate later, leading to an overall shift in the composition of the film as a function of collection time. Growth rates of film thickness are at least 0.05 nm/day based on a limited number of individually calibrated ions.
室内表面的有机膜无处不在，但对于其在不到一个月的时间尺度内的组成和生长的详细信息，我们还不完全了解。为了解决这些理解上的差距，在 17 天的时间内，使用被动采样器从公寓单元中收集有机膜样本，并使用实时直接分析质谱（DART-MS）以非靶向方式进行分析。总体而言，在公寓内各个位置观察到的化学成分非常相似。质谱还清楚地表明，来自天然来源和消费品（如羧酸和增塑剂）的半挥发性化合物的生长。某些化合物的平衡证据主要与基于辛醇-空气分配系数（）的表面分配模型一致。分子量或 值较高的化合物往往平衡较晚，导致随着收集时间的推移，膜的组成发生整体变化。基于有限数量的单独校准离子，膜厚度的生长速率至少为 0.05nm/天。
