Research Of SBSE-GC/MS Applied To The POPs In The Surface Water

With the development of science and technology and the progress of society,environment pollution appeared.People pay more attention to water quality.Persistent organic pollutions are difficult to naturally degrade in the environment.Although their content in the water is very low,they have characteristics of persistance,high toxicity,bioaccumulation and long-distance migration,which cause great threat to human's health.This thesis established a fast and simple analytical method for the determination of different kinds of ultratrace POPs in the surface water with stir bar sorptive extraction(SBSE)technology.In the first part,current pretreatment technology and detection methods of different kinds of POPs in the surface water were discussed.The advantages and disadvantages of liquid-liquid extraction,liquid phase microextraction,solid phase extraction,solid phase microextraction and stir bar sorptive extraction for POPs in the surface water were all discussed.In the second part,a fast and sensitive analytical method for the ultra trace determination of 16 kinds of polycyclic aromatic hydrocarbons(PAHs)in surface water samples based on SBSE technology with gas chromatographymass spectrometry was established.Multiple stir bars simultaneous enrichment with sequential cryofocusing and merged injection technique was used to effectively solve the problem of long adsorption time and small sample volume with SBSE.The conditions of thermal desorption unit(TDU)thermal desorption time,cooled injection system(CIS)cryofocusing temperature,CIS desorption time and extraction time were investigated.Under the optimized conditions,the results showed the linear range was between 0.2 ng/L and 10 ng/L(naphthalene,0.5?10 ng/L),and the method detection limits of the 16 PAHs ranged from 0.03 ng/L to 0.20 ng/L(naphthalene,0.50 ng/L).The 11 kinds of PAHs were determined in the surface water sample of Qiantang River,and the contents were between 0.13 ng/L and 1.57 ng/L.The recoveries of the 16 PAHs spiked in samples at different levels were between 75.6% and 108.9%.In the third part,a fast and sensitive analytical method based on stir bar sorptive extraction(SBSE)technology with gas chromatography–tandem mass spectrometry was developed to simultaneously analyse 18 kinds of polychlorinated biphenyls(PCBs)and 20 kinds of organochlorine pesticides(OCPs)in aqueous samples.Long adsorption time and small sample volume,which are problems encountered in conventional methods of SBSE,were effectively solved by simultaneously using multiple stir bars for enrichment with sequential cryofocusing and merged injection.Optimised results showed good linear coefficients in the range of 10 to 500 ng/L and the method detection limits of 0.12–2.07 ng/L for PCBs and OCPs.Four types of the studied compounds were determined in Qiantang River water samples,and their contents were between 0.82 and 5.00 ng/L.The recovery ratios of the spiked samples at different concentrations were between 64.7% and 111.0%,and their relative standard deviations ranged from 0.9% to 17.6%.