RESUMEN
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.