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采用顶空固相微萃取谱-气相色谱-质谱联用法对饮用水中2-甲基异茨醇、土味素、2-甲氧基-3-异丙基吡嗪、2-甲氧基-3-异丁基吡嗪、2,4,6-三氯苯甲醚和2,3,6-三氯苯甲醚共6种致嗅化合物进行了分析。通过对固相微萃取纤维的类型、解吸附时间、NaCl溶液浓度、溶液pH、顶空温度、转速、顶空时间等顶空条件及GC-MS条件的优化,建立了一次性顶空固相微萃取快速测定饮用水中6种致嗅化合物的方法。采用0.10 mol/L的NaOH溶液将水样调至pH 6.0。以DVB/Carboxen/PDMS涂层的固相微萃取纤维头对20 mL添加了NaCl溶液浓度为0.3 g/mL的水样于70℃水浴顶空萃取25 min。被萃取的致嗅化合物于250℃解吸附4 min供GC-MS分析。6种致嗅化合物在0.25～100 ng/L范围内线性关系良好(R>0.986),检出限低于0.1 ng/L。对实际水样进行分析,低、中、高3种不同浓度的加标回收率为93.0%～106.6%,相对标准偏差为3.0%～6.6%(n=6)。该分析方法可对饮用水中6种致嗅化合物进行同时监测。
Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (GC-MS) was used to determine the concentration of 2-methylisoxetine, urotropin, 2-methoxy-3-isopropylpyrazine, 3-isobutyl pyrazine, 2,4,6-trichloroanisole and 2,3,6-trichloroanisole were analyzed. Through the optimization of the headspace conditions and the GC-MS conditions, the type of SPME fiber, the desorption time, the concentration of NaCl solution, the pH of the solution, the temperature of the headspace, the rotational speed, the headspace time and so on, Microextraction method for rapid determination of six kinds of olfactory compounds in drinking water. The water sample was adjusted to pH 6.0 using 0.10 mol / L NaOH solution. The headspace of solid-phase microextraction fiber with DVB / Carboxen / PDMS coating was extracted with 20 mL water solution with NaCl concentration of 0.3 g / mL for 25 min at 70 ℃. The olfactory compounds extracted were desorbed at 250 ° C for 4 min for GC-MS analysis. The six olfactory compounds showed good linearity (R> 0.986) in the range of 0.25-100 ng / L with the detection limit lower than 0.1 ng / L. The actual water samples were analyzed. The recoveries were 93.0% -106.6% with relative standard deviations of 3.0% -6.6% (n = 6). This method of analysis allows simultaneous monitoring of six olfactory compounds in drinking water.