| Perfluorinated compounds(PFCs)in the environment are persistent organic pollutants and has the non-hydrophilic and non-lipophilic properties.They are difficult to decompose by photolysis,hydrolysis,oxidation and microbial degradation,and have a variety of toxicity such as reproductive,neurological and immune toxicity.PFCs are ubiquitous in the environment and pose a great threat to the ecological environment and human health.Therefore,how to quickly detect and efficiently remove the content of PFCs in environmental water and inhibit the migration of PFCs in the environment to pollute soil and groundwater has become a problem that needs to be solved for promoting the national economic and social development.For the current standard detection methods,PFCs are firstly enriched by solid phase extraction column and then detected by chromatography-mass spectrometry.Although this method has very good detection sensitivity,but the operation is complex,time-consuming,and the detection cost is high.This method can only be performed in a well-equipped laboratory.At present,most PFCs adsorption materials have the problems of low selectivity,insufficient adsorption capacity and difficult to recycle.The traditional "field sampling and laboratory analysis" mode has high cost,which is difficult to meet the needs of rapid detection,and is not conducive to timely warning and traceability of pollution.Therefore,it is of great practical significance to develop new materials with high adsorption efficiency and good repeatability to extract PFCs,achieve high-throughput separation and removal of PFCs from environmental samples and in situ rapid monitoring,for the removal and pollution warning of PFCs.The intermediates of PFCs are mainly perfluorboxylic acid(PFCAs),among which Perfluorooctanoic acid(PFOA)is the representative substance and mainly exists in water.It has great harm to environmental quality and human health,so this paper mainly studies the detection of PFOA in the environment.In this paper,4-vinylpyridine(4-vp)was selected as the functional monomer,divinylbenzene(DVB)as the cross-linker,polyethylene glycol 4000 as the dispersant,and magnetic fluid were added to prepare the magnetic solid phase microextraction column,Magnetic intube solid phase microextraction column(M-IT-SPME).The anti-magnetic force of organic matter in magnetic field was used to improve the recovery efficiency of samples and improve the enrichment factor.Finally,PFCAs in water were detected by indirect UV capillary electrophoresis.Main research contents of this paper are as following:In the first part,polymer with good adsorption effect on PFOA was prepared by bulk polymerization method.The influence of solution p H,initial concentration,temperature and adsorption time on the adsorption effect was studied,and the optimal adsorption conditions were determined.Langmuir and Freundlich models were used to analyze the adsorption characteristics.It was found that the saturated adsorption capacity of PFOA by the polymer was 261.97 mg/g,and the removal rate was up to98.99%.Hydrogen bonding and hydrophobic interaction were mainly involved to adsorb PFOA,and the adsorption effect did not decrease after six sorption-desorption cycle experiments.Its good mechanical stability and adsorption properties are expected to be used as adsorption materials in emergency treatment of PFCAs.In the second part,the magnetic in-tube Solid phase micro ex-traction(M-ITSPME)column was prepared.Different magnetic/non-magnetic and molecularly imprinted/non-molecularly imprinted extraction columns were designed.The extraction conditions were optimized,such as the kind of extracting agent,magnetic field intensity,sample p H,flow rate,etc.Under the optimal experimental conditions,the elution volume was 600 μL,water p H was 6.0 and the magnetic field intensity was 48 Gs.In addition,the adsorption selectivity of the extraction column was studied,and it was found that the extraction column had certain selectivity for PFOA.The extraction effect did not decrease after six sorption-desorption cycle experiments.In the third part,the M-IT-SPME column is combined with capillary electrophoresis technology to realize the enrichment and detection of various PFCAs in water samples.The Pearl River water samples were collected,and mixed PFCAs solution was added to the water samples.After seven parallel experiments,it was found that the recovery rate of Pearl River water samples was between 52.61 and 97.56 %,and the detection limit was between 0.14 and 0.23 μg/L,with good reproducibility and good reproducibility. |
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