Abstract: A method for the simultaneous determination of 13 benzene series (BTEX) in seawater using gas chromatography-mass spectrometry with static headspace extraction (HS-GC/MS) was developed. To carefully characterize the performance of this method, several factors affecting parameters were studied in detail, such as the type of column, heating procedure, equilibrium temperature, equilibrium time and the volume ratio of gas phase to liquid phase. The optimized conditions were as follows: the polar column of DB-WAX; heating procedure, 40 ℃ kept for 4 min, then raised to 120 ℃ at 10 ℃/min, to 180 ℃ at 25 ℃/min; equilibrium temperature, 80 ℃; equilibrium time, 10 min; and the volume ratio of gas phase to liquid phase, 1:1. Under the optimized conditions, the linear equations were obtained in the concentration range of 0.16~320 μg/L with correlation coefficients greater than 0.999. The limits of detection (S/N=3) were 0.019~0.033 μg/L. The recoveries at the three spiked levels of 1.6, 16 and 160 μg/L ranged from 81.25% to 103.73% with the relative standard deviations (RSD, n=6) from 0.3% to 4.4%. The analytical results of the practical seawater samples from Shanghai Huangpu District were satisfactory. The determination of the 13 benzene series can be finished in 12 min. The method is simple, accurate, reliable, efficient and environmental-friendly.

Key words: benzene series, gas chromatography-mass spectrometry （GC-MS）, seawater, static headspace extraction