Head-Space GC Determination of Residual Amounts of Benzene, Toluene, Ethylbenzene, m-Xylene and n-Hexane in Characteristic Agricultural Products

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%.