分散液液微萃取-气相色谱-质谱法测定长江水体中18种苯系物

GC-MS Determination of 18 Benzene Homologs in Waters of Yangtze River with Separation by Dispersive Liquid-Liquid Microextraction

取经滤膜过滤的长江水样8.00mL,加入含四氯乙烯10μL的丙酮0.50mL,样品中的苯系物在几秒钟内即被萃取至四氯乙烯微小液滴中。经高速离心,萃取相沉积在离心管底部,移取萃取相8μL置于进样瓶中供气相色谱-质谱分析。在气相色谱分离中用HP-INNOWAX毛细管柱为固定相,在质谱分析中采用全扫描和选择离子检测模式。18种苯系物的质量浓度在1 000μg·L-1以内与其峰面积呈线性关系。方法的检出限(3S/N)在0.055~0.156μg·L-1之间。加标回收率在66.5%~106%之间,相对标准偏差(n=5)在3.1%~8.6%之间。

8.00 mL of the filtered river water sample was taken treated by DLLME with 0.50 mL of acetone(containing 10μL of Cl2-C=C-Cl2),and the 18 benzene homologs were extracted into the micro-droplets of Cl2-C=C-Cl2 within a few seconds.After centrifugation at high-speed,the extract-phase was separated at the bottom of centrifuging tube.8μL of the extract-phase was taken and placed into the sample bottle for GC-MS analysis.The HP-INNOWAX capillary column was used for GC separation and the full-scanning mode as well as the selected ion monitoring mode was adopted in MS determination.Linear relationships between values of peak area and mass concentration of the 18 benzene homologs were kept in ranges within 1 000μg·L-1.Detection limits(3S/N)found were ranged from 0.055 to 0.156μg·L-1.Values of recovery found by standard addition method were in the range of 66.5%-106%,with RSD′s(n=5)in the range of 3.1%-8.6%.