GC Determination of Benzene Homologues in Air near Petrol Station with Needle Trap Extraction

The contents of benzene homologues, including methylbenzene, ethylbenzene, o, p and m-xylene in air near petrol station were determined by GC. The benzene homologues in sample were collected and enriched by needle trap extraction, and thermo-desorbed and determined by GC. SE 30 capillary chromatographic column (30 m×0.25 mm, 0.33 μm) was used for separation, and hydrogen flame ionization detector was adopted for detection. Values of detection limit (3S/N) of the method found were in the range of 0.36-1.32 μg. Tests for recovery and precision were made by standard addition method, values of recovery and RSD′s (n=5) found were in the ranges of 94.1%-104.5% and 4.9%-8.7%.