顶空气相色谱法测定工作场所空气中的氯化苦

Dertermination of chloropicrin in workplace air by headspace gas chromatography

目的建立顶空气相色谱法测定工作场所空气中氯化苦的方法。方法用无水乙醇为吸收液,多孔玻板吸收管采集空气中的氯化苦,取吸收液,在温度70℃条件下,顶空加热平衡20 min,采用顶空气相色谱电子捕获检测器测定工作场所空气中氯化苦的浓度。结果氯化苦浓度在0.05μg/ml^2.00μg/ml时具有良好的线性关系,相关系数r=0.999 8,方法检出限为0.000 78μg/ml(进样量为250μl)。最低检出浓度为0.001 7 mg/m3(采样体积为2.25 L,吸收液总体积为5 ml),平均回收率为98.0%~99.0%,相对标准偏差为3.10%~6.34%,样品在4℃冷藏箱内放置,至少可保存10 d。结论本方法操作简便、特异性强、灵敏度高、准确度好、吸收液配制简单,克服了氯化苦与乙醇钠分解反应慢的缺点,缩短了检测时间,特别适用于突发性事件的快速检测。各项指标均符合GBZ/T 210.4—2008的要求,满足工作场所空气中氯化苦测定的要求。

Objective To establish a method for chloropicrin determination in workplace air by headspace gas chromatography.Methods Absolute alcohol was used as absorption solution,chloropicrin in air was collected by fritted glass disk bubbler.Took the absorption solution with headspace heating balance for 20 minutes at 70 ℃. And the chloropicrin concentration was determainted by headspace GC-EDC. Results Good linearity（ r = 0. 999 8） was obtained when concentration of chloropicrin was in range from 0. 05 μg / ml to 2. 00 μg / ml,the method detection limit was 0. 000 78 μg / ml（250 μl injection volume）,the minimum detectable concentration was 0. 001 7 mg / m3（2. 25 L sampling air volume in 5 ml absorption solution）,the average recovery rate was during 98. 0%-99. 0%,with RSDs of 3. 10%-6. 34%. Samples could be stable in refrigerator at 4 ℃ for at least 10 days. Conclusion The method is simple,specificity strong,sensitive and accurate,and the preparation for absorption solution is easy,the determination method overcomes the shortcoming about the slow speed of chloropicrin and sodium ethoxide decomposition reaction,shortens the detection time,is especially suitable for the rapid test of emergency. Each index meets the requirements of GBZ / T 210. 4—2008 and is suitable for the determination of chloropicrin in workplace air.