采用柱净化与分散液液微萃取相结合的样品前处理方法,在去除油田水域中直链烷烃等干扰物的同时,对多环芳烃类污染物(PAHs)进行纯化富集,并利用气相色谱/质谱进行分析.分别考察了柱填料的种类、柱填料与上液量的质量比、柱流速、萃取剂种类及体积、分散剂种类及体积等对萃取效率的影响,最终选择12 g H103大孔树脂为柱填料,以柱填料/样品质量比为12:5上样,在4倍体积/小时(BV/h)柱流速下过柱吸附干扰物,洗脱液加入1.00 mL丙酮(分散剂)和15 μL四氯化碳(萃取剂)后进行分散液液微萃取2 min.在最优条件下,PAHs的富集倍数为730~1579,检出限(S/N=3)为1.1~5.3 ng/L,线性范围为0.01~50 μg/L,相对标准偏差(n=5)为0.6% ~3.4%,回收率为82.6% ~104.6%.本方法最大程度地降低了基质中干扰物对分析结果的影响,提高了方法的准确性,操作简单方便,尤其适用于受污染油田水体的快速分析.%A sample pretreatment method combining column clean-up with dispersive liquid-liquid microextraction (CCU-DLLME) for determination of polycyclic aromatic hydrocarbons (PAHs) in oil-field water was proposed. With this method,most organic interferences in matrix were cleaned up,and PAHs were purified, enriched and analyzed by gas chromatography/mass spectrometry directly. The influences on extraction efficiency including the kinds of column packing,weight ratio between column packing and sample, column flow rate,type and volume of extraction solvent, type and volume of disperser solvent and extraction time were investigated, respectively. Finally, 12 g of H103 macroporous resin was selected as column packing,12﹕5 of weight ratio between column packing and sample and 4 BV/h of column flow rate were selected in CCU. The resulting eluate was added with 1.00 mL of acetone (disperser solvent) and 15 μL of carbon tetrachloride (extraction solvent),followed by DLLME for 2 min. Under the optimum conditions,the enrichment factor of PAHs was 730-1579,the limits of detection (S/N=3) were 1.1-5.3 ng/L, the linear range was 0.01-50 μg/L,the RSDs(n=5) were 0.6%-3.4% and the recoveries were 82.6%-104.6%. This method could greatly reduce the influence of organic interferences in matrix, and was fit for the rapid analysis of pollutants in oil-field water especially.
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