Analysis Of 78 Organic Pollutants In Soil By Two-dimensional Gas Chromatography-time Of Flight Mass Spectrometry

The environmental and ecological security problems caused by soil pollution in China can not be underestimated,and should be paid enough attention.The Plan of Action for the Prevention and Control of Soil Pollution issued by the State Council claims to carry on the work of soil environmental protection,carry clearly on soil environmental quality survey and promote the construction of ecological civilization to achieve sustainable development.Soil organic pollutants in China are persistent,migrable,enrichable and difficult to repair.It is urgent to find effective methods for the analysis and determination of a wide variety and new types of organic pollutants in order to provide a strong support for the following soil restoration and protection work.A analysis method for the determination of 78 organic pollutants in soil by GCxGC-TOF-MS was purposed.The method is also experimented by real field samples.The main research contents are as follows:This paper comprehensively collected,collated and utilized the existing literature and technical data,such as China soil environmental quality standard GB 15618-1995 and the US EPA 8270 and the Black List of Pollutants with top priority in China to decide 78 kinds of organic pollutants were identified as the research object,including polycyclic aromatic hydrocarbons,organochlorine pesticides,pyrethroids,organophosphorus pesticides,herbicides and other pesticides,chemical pollutants and their intermediates,metabolites,etc.In this study,the condition of instrumental analysis GC×GC-TOF-MS were optimized.The stability,sensitivity,quality of the qualitative and quantitative analysis were ensured and proved by the purposed instrumental analysis method optimization.The parameters of the instrument meet the requirements.The linear range of the targets was between 10 ng/mL-500 ng/mL,the correlation coefficient(r2)was between 0.9957-0.9999.The precision of the instrument(RSD)was between 1.02-10.8.The instrument detection limit ts was in 0.49 ng/mL-12.5 ng/mL.It had good sensitivity and stability,and met the requirements of trace analysis.In this study,Soxhlet extraction method was used for pretreatment analysis.The n-hexane:dichloromethane(1:1 v:v)mixed solvent was selected as extraction solvent.The recovery rates of gamma-chlordane,alpha-chlordane,hexachlorobenzene at low concentration level were relatively low.Dimethoate and chlorpyrifos at high concentration level were relatively low.And interference of di(2-ethylhexyl)phthalate and diisobutyl phthalate is serious.The average recovery of the other targets was between 75.1-115%,RSD ranges were from 0.95 to 14.0.And method detection limits were between 0.5-3.5ng/g.which satisfied the experiment requirement.The total detection rate of 30 samples in the field was 100%.All samples had targets detected.Among them,polycyclic aromatic hydrocarbons(PAHs)were detected more frequently,ranging from 3.33%to 30.0%,15 of 16 types of PAHs were detected.Other organophosphorus and organochlorine pesticides and o-phenylphenol were also detected too.This method has reliability,feasibility and operability to satisfy simultaneous analysis of multiple kinds of targets,and meets the requirements of analysis and testing.