| Polycyclic aromatic hydrocarbons(PAHs)derivatives were formed by PAHs through the reaction with NxOy,OH and O3.PAHs have been listed as the environmental priority pollutants by the United States Environmental Protection Agency(USEPA)owing to their potential "three toxic effects"(carcinogenicity,teratogenicity,and mutagenicity)in the 1970s.In recent years,PAHs derivatives have been got a great attention because studies showed that some PAHs derivatives are more toxic than their parents.Groundwater is an important source of drinking water and water for industry and agriculture.Some mobile PAHs derivatives are easy to enter groundwater through precipitation,atmospheric sedimentation,surface runoff and other pathways,thus they threat the safety of groundwater.However,there are few reports on PAHs derivatives in groundwater.Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry(GC×GC-TOFMS)is a new technology developed in recent years.It’s one of the strongest analytic technologies for separation of complex mixture by maximizing the orthogonality of different GC column combinations and improving the separation of PAHs from the sample matrix interferences.In this study,the technology was used to establish a rapid,sensitive,precise method for simultaneous analysis of 75 emerging PAHs derivatives and their parents in groundwater.The study would greatly enhance the ability of rapid separation and analysis of polycyclic aromatic hydrocarbons(PAHs)in groundwater and would also offer technical support for further study on PAHs derivatives in groundwater.The research achievements are as follows:1.The Confirmation of the targetd compounds79 polycyclic aromatic hydrocarbons(PAHs)derivatives and their parents were selected as the target compounds,including 14 EPA PAHs,18 methyl-PAHs,15 nitro-PAHs,11 oxy-PAHs,5 N-PACs,3 thio-PAHs and 2 halogenated-PAHs and 11 other PAHs.2.Establishing instrument analysis methodAn accurate and sensitive method was developed for analysis of 75 polycyclic aromatic hydrocarbon derivatives by using two-dimensional gas chromatography coupled with time-of-flight mass spectrometry.The method solves the difficulty in separating the multicomponent targets owing to large differences in physicochemical properties of various isomers.Apart from biphenyl and 1,2,3,4-tetrahydronaphthalene,the method has good linearity in the range of 0.1～1000μg/L with the correlation coefficients(r)greater than 0.99 and meet the analysis requirements.3.Establishing pre-treatment analysis methods of groundwater samplesIt is difficult to get high recoveries of all the substituted and parent PAHs with different physical and chemical properties,simultaneously.This paper developed comparative study of liquid-liquid extraction,solid phase extraction and solid phase microextraction.Liquid-liquid extraction was selected as the pretreatment analysis method.Spiked recoveries of analytical targets ranged from 58.2%to 118%,except for acridine,9,10-dinitroanthracene,dibenzo[a,j]acridine and 1-nitropyrene.The relative standard deviations ranged from 2.46%to 22.6%,and the method detection limits ranged from 1.26 ng/L to 22.49 ng/L.4.Screening of PAHs derivatives in groundwaterThe contents of polycyclic aromatic hydrocarbons(PAHs)derivatives and their parents in groundwater in parts of eastern China were investigated.For the first time,most of targets were detected in Chinese groundwater.Among them,methy-PAHs has the highest detection rate(60%)which means it was ubiquitous in groundwater and other PAHs were detected with different concentrations.In Hebei Province,the concentrations of target compounds were high in CD,XT and CZ but low in other cities.The work studied the distribution characteristics of polar,mobile PAHs derivatives from north to south and found the concentrations of S-PACs and nitro-PAHs were high in the south but low in the north and when it comes to oxy-PAHs the situation is reversed.The results indicated that groundwater was in low level of pollution of parts of China and it deserves our serious attention. |
