提出了固相微萃取样品-气相色谱法测定水中7种苯系物(苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯和异丙苯)的含量。为使固相微萃取达到更高的效率,选择75 μm的CAR/PDMS作为萃取头的涂层,萃取温度及时间为20 ℃和40 min,在10 mL试样溶液中加入氯化钠4 g作为盐析剂。用DB-FFAP毛细管色谱柱分离,氢火焰离子化检测器检测。7种苯系物的质量浓度均在1.00~500 μg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.12~0.19 μg·L-1之间。方法用于4种环境水样分析,加标回收率在93.3%~104.2%之间。

GC with sample pretreatment by solid phase micro-extraction (SPME) was applied to the determination of 7 benzene homologues, i.e., benzene, methylbenzene, ethylbenzene, p-xylene, m-xylene, o-xylene and cumin, in water samples. To attain a higher efficiency for SPME, the 75 μm CAR/PDMS coating was applied to the micro-extractor, and the extraction was carried out at 20 ℃ for 40 min, with addition of 4 g NaCl to 10 mL of sample solution as salting out agent. The analyte were separated on DB-FFAP capillary column and detected by hydrogen FID. Linear relationships between values of peak area and mass concentration of the 7 benzene homologues were kept in the same range of 1.00-500 μg·L-1, with detection limits (3S/N) in the range of 0.12-0.19 μg·L-1. The proposed method was applied to the analysis of 4 environmental water samples, giving values of recovery found by standard addition method in the range of 93.3%-104.2%.