A Fast And Efficient Method For The Analysis Of Typical Semi-volatile Organic Compounds In Soil

The organic pollution of soil is very serious in China and abroad,which endangers the safety of agricultural products and human health.Efficient and rapid analysis of organic pollution in soil is very important to soil pollution risk control,soil treatment and remediation.Semi volatile organic pollutants(SVOCs)are the main organic pollutants in soil,which have the characteristics of wide source,coexistence of multiple pollutants,difficult degradation and high toxicity.At present,the commonly used semi-volatile organic compounds analysis methods have the limitations of unitary test and cumbersome pretreatment of multiple organic compounds.This paper is based on accelerated solvent extraction,solid phase chromatography column purification and gas chromatography-mass spectrometry.The simultaneous determination methods of 11 kinds of SVOCs(including aniline,2-chlorophenol,nitrobenzene,naphthalene,benzo(a)anthracene,chrysene,benzo(b)fluoranthene,benzo(k)fluoranthene,benzo(a)pyrene,indeno(1,2,3-cd)pyrene and dibenz(a,h)Anthracene)in soil were established.The main research contents and results are as follows:(1).A gas chromatography-mass spectrometry(GC-MS)condition was established to analyze the 11 SVOCs in soil.The split ratio of injector was optimized to be 10:1,the temperature of vaporizer was300℃,as well as a heat program of column oven was set up: the initial temperature was 35℃ kept for 2 minutes,then increasing to 70℃ at the rate of 10℃/min,then increasing to 90℃ by 10℃/min hold for 1 minute,finaly increasing to 300℃ by 15℃/min,remaining 300℃ for 15 min.(2).The conditions of accelerated solvent extraction(ASE)were optimized in this study.The single factor experiment of temperature,pressure and extraction solvent were studied in order to increasing the recovery of 11 kinds of SVOCs.N-hexane-acetone(1+1)was selected as the best solvent in three kinds of extraction solutions by the orthogonal experiment.On this condition,we found the average recovery of 11 kinds of SVOCs was the highest when extraction temperature at 65℃ and the pressure of ASE was set at 120 bars,which is ranging from 66.4% to105.8%.(3).We modified the solid phase extraction(SPE)conditions of florida silica column.The elution efficiencies of three different eluents were compared.Finally,10 m L acetone-n-hexane(1+9)and 5 ml isopropanol-n-hexane(1+4)was select to used as gradient elution,the recoveries of targets were 65.6%～100.8%.(4).According to the standard HJ 168-2020,the method detection limits(MDLs)of 11 kinds of SVOCs in this methord were between 0.001mg/kg-0.004 mg/kg,the accuracy(recovery range)were 64.3% ～113.6%,and the precision(RSD)were 0.5%～16.0%.(5).The detection rate of 11 kinds of SVOCs in 31 development land samples was 96.8%.And it turned out that this methord could meet the requirements of analysis and testing.Compared with HJ 834-2017,two-thirds of the pre-processing steps were reduced by this methord.So the methord is faster,labor-saved,and more friendly to the environment.