On-line multi-bed sorption trap for VOC analysis of large-volume vapor samples: injection plug width, effects of water vapor and sample decomposition
On-line multi-bed sorption trap for VOC analysis of large-volume vapor samples: injection plug width, effects of water vapor and sample decomposition
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DOI：
10.1002/jssc.200401881
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发表时间：
2005-01-01
影响因子：
3.1
通讯作者：
Sacks, RD
中科院分区：
文献类型：
--
作者：
Sanchez, JM;Sacks, RD
多床在线吸附阱用于预浓缩空气样品中的有机蒸气，并将分析物注入GC分离柱。注入塞宽度取决于亲脂性化合物的沸点和极性化合物的极性和沸点。注入塞宽度足够小（0.7 - 0.8秒），以允许将最易挥发的化合物直接注入GC柱中，而不需要第二聚焦装置。样品中水的存在对捕集器保留极性化合物有影响。然而，对于固定的水含量，这种效应是可再现的，因此可以通过在与样品相同的湿度条件下使用校准标准来克服。本文研究了在气相色谱分析空气样品时，许多挥发性有机化合物在在线吸附捕集器中的热分解。结果表明，不稳定化合物的降解受解吸过程中传递给化合物的热量控制（即，施加的温度和脉冲持续时间）。在线捕集器的使用导致解吸的化合物立即转移到分析柱，这可以减少人工产物的形成。
A multibed on-line sorption trap is used to preconcentrate organic vapors from air samples and inject the analytes into a GC separation column. Injection plug widths depend on the boiling point for the lipophilic compounds and on the polarity and boiling point for the polar compounds. Injection plug widths are sufficiently small (0.7 - 0.8 s) as to allow the direct injection of the most volatile compounds into the GC column without the need for a second focusing device. The presence of water in the samples has an effect on the retention of polar compounds by the trap. However, this effect is reproducible for a fixed water content and so can be overcome by using calibration standards under the same conditions of humidity as the samples. The thermal decomposition of many volatile organic compounds in an on-line sorption trap during the GC analysis of air samples is examined. The results show that degradation of unstable compounds is governed by the amount of heat transferred to the compounds during desorption (i.e., applied temperature and pulse duration). The use of an online trap results in the immediate transfer of desorbed compounds to the analytical column, which can reduce the formation of artifacts.