建立了惰性气体一表面活性剂辅助液液萃取与气相色谱联用测定水中多环芳烃的方法。向添加有适量表面活性剂的250mL水样中导入惰性气体,气泡将包裹待测物的胶束带到水样上层1mL有机相中,并在其中浓缩,将上层有机相经过无水硫酸钠干燥后定容至1mL,采用气相色谱一火焰离子化检测法(GC—FID)测定。考察了不同表面活性剂、有机溶剂、氮吹时间和表面活性剂浓度对萃取效率的影响。建立的方法具有有机溶剂使用量少、可自动化操作和批量处理样品等特点。工作曲线具有良好的线性关系,相关系数〉0.997,以FID为检测器,富集倍数为250时,定量限为10~20μg/L,检出限为1~5μg/L,重复测定的相对标准偏差〈7%(n=5)。采用建立的方法对实际水样进行测定,加标回收率为86%~108%。
A method for determination of polycyclic aromatic hydrocarbons(PAHs) in water by inert gas/ surfactant-assisting liquid-liquid extraction combined with gas chromatography (GC) was developed. The inert gas blew though surfactant-containing water to generate bubbles,which took PAHs molecules in micelles to the organic phase. The water in the organic phase was removed by anhydrous sodium sulfate. The PAHs concentration was measured by GC with a flame ionization detector. The influences of various surfactants and organic solvents, nitrogen blowing time and surfactants concentration were studied. Samples could be treated automatically with small amount of organic solvent. An enrichment factor of 200,quantification limits of 10-20 μg/L and detection limits of 1-5 μg/L were obtained with good linearities(R〉0. 997). The RSDs were lower than 7G and the recoveries were 86%-108% for real sample analysis.