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    吸附萃取搅拌棒在火场空气中助燃剂残留物的采集取样中的应用

    Application of Stir Bar of Sorptive Extraction to Sampling of Residues of Combustion Adjuvants in Air over Fire Field

    • 摘要: 对微吸附采样技术进行改进,采用带有活性炭/聚二甲基硅氧烷涂层的长度为20 mm的吸附萃取搅拌棒对火场空气中助燃剂残留物进行采集取样。将上述吸附萃取搅拌棒装于采集取样装置的前端,采集取样装置的后端与空气泵连接。在空气泵流量为50 mL·min-1,采集时间为60 s,采集温度为30℃的条件下进行采集取样。样品采集完成后,将吸附萃取搅拌棒直接放置于热分离进样杆中进样,对助燃剂残留物样品进行气相色谱-质谱法分析。当分析对象为汽油,采集时间为60 s时,方法的检出限(5S/N)为0.1 μL·L-1;当采集时间增加至300 s时,检出限(5S/N)可降至1 nL·L-1。分析95#汽油时,用AMDIS软件对总离子流色谱图进行分析,1 μL·L-1的汽油样品中检出400种特征化合物。除汽油外,还对航空煤油、柴油、乙醇和乙酸乙酯等助燃剂的残留物进行定性分析。

       

      Abstract: As a modification for the micro-adsorption sampling technique, a stir bar of sorptive extraction, having a length of 20 mm and coated on its surface with activated carbon and poly-dimethylsiloxane, was used in the sampling of residues of combustion adjuvants in air over fire field. The stir bar of sorptive extraction was placed into the holder in the front position of the sampling device, which was connected with the air pump at the rear. Sampling of the sample was accomplished under the following conditions:(a) flow rate of air pump was 50 mL·min-1; (b) acquisition time was 60 s; and (c) acquisition temperature was 30℃. At the end of sampling, the stir bar of sorptive extraction was replaced into thermal separation probe of injection to have the sample of residues of combustion adjuvants for GC-MS analysis. As gasoline was the analyte and acquisition time of 60 s was taken, detection limit (5S/N) of the method of 0.1 μL·L-1 was attained, and detection limit (5S/N) could be lowered to 1 nL·L-1 when acquisition time of 300 s was taken. In analysis of 95# gasoline, with volume fraction of 1 μL·L-1, 400 characteristic compounds were detected from the TIC chromatogram with help of the soft ware AMDIS. Besides gasoline, aviation kerosene, diesel oil, ethanol and ethyl acetate were the 4 other combustion adjuvants, the residues of which were also be qualitatively analyzed by the proposed method.

       

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