采用顶空-气相色谱法测定特色农产品中苯、甲苯、乙苯、间二甲苯和正己烷的残留量。选择顶空进样器的平衡温度和时间分别为130 ℃和50 min,用DB-624色谱柱分离,火焰离子化检测器检测。5种化合物的质量浓度均在30 mg·L-1以内与其峰面积呈线性关系,方法的检出限(3S/N)在0.3~0.6 mg·L-1之间。在3个浓度水平上做回收试验,回收率在88.1%~103%之间,相对标准偏差(n=6)在0.38%~2.8%之间。

Head-space GC was applied to the determination of residual amounts of benzene, toluene, ethylbenzene, m-xylene and n-hexane in characteristic agricultural products. The equilibrium temperature and time of head space sampler were set at 130 ℃ and 50 min, respectively. The analytes were separated on DB-624 column and detected by FID. Linear relationships between values of peak area and mass concentration of the 5 compounds were kept in the same range within 30 mg·L-1. Detection limits (3S/N) found were ranged from 0.3 to 0.6 mg·L-1. Tests for recovery were performed by addition of mixed standard of the 5 compounds at 3 concentration levels for 6 parallel determinations, results of recovery found were in the range of 88.1%-103% with RSD′s in the range of 0.38%-2.8%.