建立了超声提取-气相色谱质谱法测定大气PM2.5中32种正构烷烃方法,经离子温度优化、前处理比较、空白滤膜考察等获得了最佳的实验条件。研究发现,高、中、低3种浓度标准曲线的相关系数均在0.995以上,3种浓度的空白样品加标回收率分别为72.2％~117.8％、73.5％~104.4％、73.8％~109.5％,精密度均小于10％,实际样品加标回收率为75.7％~108.9％。当采样体积为24 m3时,各目标化合物的方法检出限为0.046~2.6 ng/m3；经正构烷烃浓度范围为0.17~64.3 ng/m3的1月及浓度范围为0.53~7.67 ng/m3的6月的实际样品验证,该方法的检出限和测量范围也可较好的满足实际样品的测定。%A method of Gas Chromatography Mass Spectrometry with Ultrasonic Extraction determination of 32 N-alkanes in PM2. 5 has been established. In order to acquire the best conditions, various parameters were studied, like as the effect of different ion source temperature, the pretreatment of the method, the selection of blank quartz filter, and investigating the adaptability of this method by detecting the actual samples. Results showed that the correlation coefficient of 32 N-alkanes in PM2. 5 detected by Gas Chromatography Mass Spectrometry with Ultrasonic Extraction were all above 0. 995, it has high accuracy and precision. In addition the recovery of 32 N-alkanes of different concentration in blank quartz filters were in the range of 72. 2%-117. 8%, 73. 5%-104. 4%,73. 8%-109. 5%, precision is less than 10%, and the recovery of actual sample was in the range of 75. 7%-108. 9%. Otherwise, When the sampling volume was 24 m3 ,the limit detection of 32 N-alkanes was 0. 046-2. 6 ng/m3 . We detected actual samples in in January and June, the concentration of N-alkanes ranged from 0. 53-7. 67 ng/m3 and 0. 17-64. 3 ng/m3 separately, With this result we can see this method has low detection limit, can completely suitable for determination of N-alkanes in PM2. 5 .
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