优化顶空-气相色谱/质谱联用法测定水中苯系物

OPTIMIZED DETERMINATION OF BTEXS IN WATER SAMPLES WITH HEADSPACE-GAS CHROMATOGRAPHY/MASS SPECTROMETER

采用VF-5ms和CP-8ms毛细管色谱柱、顶空-气相色谱/质谱联用法测定水中的苯系物，并对实验条件，尤其是顶空条件进行了优化。结果表明，含有水样的10 ml顶空瓶在加热阱以500 r min-1振摇20 s，停90 s，液气比为6：4，加盐（NaCl）量为0.4 g ml-1，于60 ℃时平衡30 min，即可达到顶空的最佳实验结果；且本方法的仪器精密度为1.41％～6.52％，检出限为0.10～0.13 μg L-1不等，实验得出各目标物的标准曲线线性相关性均为r≥0.999，加标样品回收率为98.4%～100.2%，完全符合有机分析的要求。

BTEXs in water samples were determined with VF-5 ms and CP-8ms capillary-column and Headspace-Gas Chromatography/Mass spectrometer （HS-GC/MS） under modified conditions, especially with the headspace. Results show that when 10 ml flasks with water sample accounting for 60% of each flask in volume were agitated for 20 sec. at a rate of 500 r min -1, in the heated shaker, then kept still for 90 sec. mixed with 2.4 g NaCl in each flask and left for equilibrium for 30 min. under 60 ℃, optimal results could be obtained. The BTEXs detection limits of the method varied the range of 0.10-0.13 μg L -1; the standard curve correlation coefficient （r） of each BTEXs target was more than or equal to 0.999; and the sample recovery rate lingered in the rang of 98.4%～100.2% with precision being 1.41%-6.52% （n=7）. All demonstrate that the method meets the requirements of organic analysis.