毛细管气相色谱法测定室内环境空气中TVOC浓度的研究

本文研究了影响气相色谱法测定室内空气中TVOC(总挥发性有机化合物)浓度的主要因素。采样过程中如流量达不到0 . 5L min ,可通过延长采样时间使最终采样体积达到10L ;采样前延长通风时间使室内外空气充分对流,有利于室内残留污染物质的扩散,能反映重新封闭后有机挥发物1h时段内释放的实际浓度。TVOC各组分的热解吸率与该组分的分子量和极性有关;热解吸率随解吸时间的延长而降低,操作中以1～3min比较合适。将初始柱温从5 0℃提高到70℃,不设停留时间,终止温度从2 5 0℃降为2 30℃,可以将样品分析时间由5 5min缩短到32min而对分析结果几乎没有影响。

STUDY ON DETERMINING CONCENTRATION OF TOTAL VOLATILE ORGANIC COMPOUND IN INDOOR AIR BY CAPILLARY GAS CHROMATOGRAPHY

The factors influencing the concentration of total volatile organic compound (TVOC) in the indoor air,which was measured by gas chromatography (GC),were studied.By prolonging the sampling time,10 L air could be taken according to the real measured flow.The sufficient convection between the indoor air and the outdoor air after longer time ventilation was beneficial to the diffusion of the harmful air from indoors to outdoors.And then when the room was closed,the concentration of TVOC in 1 hour could be accurately measured.The thermal desoprtion rate of the single component was affected by its molecule weight and polarity; and the thermal desoprtion rate decreased with desorption time.The measuring time could be shortened if the initial and final coulmn temperatures were changed from 50 to 70 ℃ and 250 to 230 ℃, respectively while the results remained unchanged.