大气有机物预浓缩用吸附剂富集特性的气相色谱法研究

用气相色谱方法研究了吸附剂对大气有机物的富集特性，提出用吸附参数泄漏体积ＢＴＶ（最大采样体积）以及脱附参数最低脱附温度或最小吹扫体积作为富集指标的新思想，并用冲洗色谱法测定了一些有机物在ＧＤＸ－３０１上的特性参数。不同温度的特性参数由１ｏｇ（ＢＴＶ）与１／Ｔｃ的线性关系外推得到。实验表明，所研究的２０种有机物（除了甲醇外）在装有２ｇＧＤＸ－３０１的采样管和０．１４ｇＧＤＸ－３０１的聚焦管上的最大采样体积分别不小于０．８Ｌ（３５℃）和０．３Ｌ（０℃）。

A Gas Chromatographic Study on the Characters of Adsorbents in the Enrichment of Organic Compounds from Air Samples

A gas chromatographic method for the measurement of enriching characters of adsorbents used in preconcentration of organic compounds from air samples was studied. The character parameters suggested in this study include adsorption parameters (breakthrough volume or maximum sample volume) and desorption ones (minimum flashing volume and the lowest desorption temperature). The parameters of some low-molecular-mass compounds such as alcohols, saturated hydrocarbons, aromatics, esters and halohydrocarbons on GDX-301 were measured by using elution GC method. The maximum sample volumes of all the 20 compounds (with exception of methanol) got from these experiments are not less than 0.8 L at 35 degrees C for sampling tube (filled with 2 g GDX-301) and 0.3 L at 0 degrees C for focus tube (with 0.14 g GDX-301). The corresponding minimum flashing volumes of less than 177 mL and 13 mL respectively are needed to complete desorption at 180 degrees C, and the lowest desorption temperatures of not over 180 degrees C and 157 degrees C at flashing volume of 180 mL and 30 mL are lower than the maximum allowable operating temperature (250 degrees C) of GDX-301. The results showed that GDX-301 is a good adsorbent for enrichment of the organic compounds mentioned above. The following operating conditions are recommended: using the above sampling tube and focus tube, actual sample volume < or = 0.8 L, adsorption temperature < or = 35 degrees C and focus temperature 0 degrees C, desorption for 6 min from sampling tube and 1 min from focus tube at 180 degrees C with flashing rate 30 mL/min. Good correlations between the parameters and boiling point of the investigated compounds were found. It can be used to estimate the parameters of other organic compounds not measured in this study.