Study On Detection Of Polycyclic Aromatic Hydrocarbons (pahs) In Soil

Polycyclic aromatic hydrocarbons (PAHs) are the oldest carcinogenic substance discovered in the nature, which located in the atmosphere or water and finally through surface run off and sedimentation into the soil. As we know, soil is the source of nutrition for plants, at the same time soil is the major storage compounds library and transfer station of PAHs, the residue of PAHs in the soil pass into the human body through the food chain, eventually make serious health risk to human . China began the research on PAHs from the 20th century since the 1980s, but the monitoring types, range and analysis methods are far away from other countries. At the same time there are few standard methods in determination of environmental protection agency (EPA)- defined 16 priority PAHs of soil in China. Because of the complexity of soil matrix and trace amount of PAHs residues, establishing high sensitive multi-residue analysis method of PAHs is most important for prefect detecting technology and standards system..This paper selects the provisions of the U.S. EPA 16 priority PAHs as the research objects, through the research, a new method using accelerated solvent extraction(ASE) combined with solid-phase extraction and using gel permeation cleanup followed by high performance liquid chromatography-tendem UV and fluorescence detector has been established for quantitative determination of 16 kinds of polycyclic aromatic hydrocarbons in soils. The major findings are as follows:1.Soil samples were extracted by accelerated solvent extraction. Compared with different extraction solvent and extraction temperature, finally determine the extraction method is as followed:In the method, the samples were extracted by ASE with acetone + dichloromethane[ψ(CH3COCH3 +CH2CL2)=50+50]at 120℃,the pressure is 1500psi, preheat 5min, static extraction 5min and cycle 2 times, then using the 60% volume of the extraction solvent to rinsing the pipeline and finally collected all the extract in the bottle after using nitrogen purge 40s.2.Using gel permeation chromatographic cleanup and combined with solid-phase extraction to purify the samples. The results demonstrated that 16 kinds of PAHs'outflow from the gel permeation column, the recovery of PAHs by different vacuum chamber concentration and the elution solvent, elution volum of the SPE, eventually establish the optimal purification method of PAHs in soil.3.Developed a method for determination of 16 polycyclic aromatic hydrocarbons (PAHs) in sources of soil by high– performance liquid chromatography (HPLC) .Through the research we know that the recoveries were 70%～120%,and the relative standard derivations(RSD) of PAHs were between 0.3% and 19.9%, while the method has good accuracy ,precision and has a good linear range and detection limit, meet more actual requirement to analysis the residual of polycyclic aromatic hydrocarbons in soil.4.This article determined the concentration of organic matter from three kinds of soil.Compared with the actual research, we know that although they had different concentration of organic matter, they all had a good recoveries under using this method, and the relative standard deviation within a specified range, at the same time this method couble be satisfactorily with a good test results, we prove its applicability.