| Polycyclic aromatic hydrocarbons (PAHs) and Polychlorinated biphenyls (PCBs) are two typical persistent organic pollutants (POPs) in complex environments. Since their long-term residual, semi-volatile and highly toxic properties, PAHs and PCBs could pose a potential risk to human and ecological environment. PAHs produce a variety of toxicity in vivo, such as cytotoxicity, genotoxicity and immunotoxicity and even lead to deformities and cancer, and so on. Concerning the endocrine disrupting effects of PCBs, it damages the reproductive and immune systems, induces cancer and neurological disease, and triggers environment "feminization", red tide and algae toxins effect, etc.. The pollution characteristics of PAHs and PCBs in environments have attracted a great deal of scientific and public attention. However, accurate an efficient and reliable analytical method of PAHs and PCBs was also highly expected due to those complex environmental media.Aiming at the deficiencies of analysis method on PAHs and PCBs in the sediment, the pre-processing (extraction and purification) conditions and instrumental analysis conditions of16PAHs and28PCBs in the sediment were optimized systemically in this paper. A method for the simultaneous extraction, cleanup, determination of28polychlorinated biphenyls (PCBs) and16polycyclic aromatic hydrocarbons (PAHs) in sediments has been developed by using accelerated solvent extraction (ASE) and solid-phase extraction (SPE) cleanup coupled with capillary gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS/MS). The method was applied to analysis the pollution characteristics of PAHs and PCBs in surface sediments which are sampled from the Caohai Lake and estuaries around Caohai Lake. Simultaneously, the feasibility of the method to complex environment medium was verified.In this paper, the ASE extraction conditions (temperature, time, etc.) and the SPE purification conditions (purification column, elution solvent, elution rate, etc.) of16PAHs and28PCBs in sediment were discussed. The results indicated that the optimal conditions of ASE were operated at90℃for6min; the Silica gel-Florisil composite columns (packing the Florida silica,0.7g activated silica gel,1g anhydrous sodium from bottom to top) was chosen as column of purification; the optimal elution solvent was mixture solvent of acetone/hexane (1:19, V/V),0.6mL/min is optimum for elution rate.16PAHs and28PCBs were detected simultaneously by using GC-QqQ-MS/MS on the basis of the pre-treatment conditions after the determination of the qualitative and quantitative analysis conditions. The results indicated that the correlation coefficients (R2) for PAHs and PCBs were0.9939-0.9999and0.9987-0.9999, respectively. The detection limits of PAHs and PCBs were in the range of0.07-0.45ng/g,0.001-0.08ng/g, and the limits of quantitation were0.24-1.67ng/g,0.003-0.25ng/g, respectively. The average recoveries of the spiked samples ranged from70.4%to124.7%with RSD (n=6) of1.1%-12.8%for PAHs, and from95.6%to125.7%with RSD (n=6) of0.7%-6.4%for PCBs. It Showed that the method could detect simultaneously PAHs and PCBs in sediment with good extraction and purification effect, high accuracy, good repeatability and less solvent consumption.The present method was applied to analyze PCBs and PAHs in surface sediments collected from the Caohai Lake and estuaries around the Lake, and the results showed that the area has been polluted by PAHs and PCBs in different levels. The total concentrations of PAHs and PCBs range from787.24to12270.62ng/g and from1883.53to78212.90ng/kg, respectively, and the maximum concentrations of them were found in sites R1and S1, respectively. The distribution characteristics of PAHs and PCBs in this study area showed that the concentrations of north being higher than the central, south and southeast. Sources analysis showed that the primary source for PAHs is the biomass (grass, wood and coal) combustion and PCBs mainly come from the use of Aroclor1248and1260. Risk assessment showed that the PAHs pollutions of S1, R1, R2and R3were relatively serious, additionally, the concentration of PCBs has reached a higher risk to induce cancer. |
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