Preparation Of Cross-linked Organic Polymer-based Solid-phase Microextraction Fiber And Their Application In Determination Of Pollutants In Environmental Water Samples

With the acceleration of the world’s industrialization process,various types of pollution discharged have caused tremendous damage to the environment on which humans depend for survival.Among them,organic pollution is the most serious,such as the increasing pollution of soil and water bodies near cities and industrial areas.Among them,organic pollutants such as polycyclic aromatic hydrocarbons,organochlorine pesticides,and phthalate esters can be directly ingested by the human body and pose a huge threat to human health.Therefore,the trace detection of pollutants in the environment is particularly important.However,due to the low concentration of organic pollutants in the environment,the complexity of the matrix,and the limitations of traditional techniques,this poses greater challenges to analysts and sample pretreatment techniques.Solid phase microextraction(SPME)integrates sampling,extraction,enrichment,and sample injection.and is simple to operate and environmentally friendly.It is widely used in food and environmental sample analysis.In this study,three kinds of porous organic polymers were prepared and used as SPME coating.Combined with gas chromatography or gas chromatography-mass spectrometry,detection methods for different organic pollutants were established.The main research contents of this paper are as follows:1.By integration of benzene-constructed porous organic polymer(named as KBF)and multiwalled carbon nanotube(MWCNT).a MWCNT-KBF hybrid material was constructed through in situ knitting benzene with formaldehyde dimethyl acetal in the presence of MWCNTs to form a network.MWCNT-KBF was then adopted as a novel solid-phase microextraction(SPME)fiber coating.Coupled to gas chromatography-flame ionization detection,the MWCNT-KBF-assisted SPME method showed large enhancement factors(483-2066),low limits of detection(0.04-0.12 μg L-1),good linearity(0.13-50μg L-1),and fifth-order parallel experiment acceptable reproducibility(4.2-10.2%)for the determination of polycyclic aromatic hydrocarbons(PAHs).The method recoveries of seven PAHs were in the range 80.1-116.3%,with relative standard deviations(RSDs)ranging from 3.5 to 11.9%.The SPME method was successfully applied to the determination of PAHs in river,pond,rain and waste water,providing a good alternative for monitoring trace level of PAHs in environmental water.2.Design and synthesis of novel coatings for solid phase microextraction(SPME)is urgently needed for sample pretreatment.In this study,three hypercrosslinked polymers(HCPs)were constructed by the facile Friedel-Crafts alkylation reactions between tetraphenylethylene(TPE)and 1,4-bis(chloromethyl)benzene(BCMB),4,4’-bis(chloromethyl)-1,1’-biphenyl(BCMBP),and cyanuric chloride(CC),respectively.The newly-synthesized HCPs were employed as SPME coatings for the extraction of phthalate esters(PAEs).Various parameters influencing the SPME efficiencies,including extraction time and temperature,ionic strength,stirring rate,desorption temperature and time were optimized.Under the optimal conditions,low limits of detection(0.003-0.033 μg L-1),wide linearity(0.01-10 μg L-1)and good repeatability for 4.1-9.3%(n=5)were achieved.The HCPs-based SPME method was successfully applied for the determination of eight PAEs in environmental water and bottled water samples with recoveries from 75.3%to 116%.This method provides a good alternative for monitoring trace level of PAEs in water samples.3.Three porous organic frameworks(POFs)linked by-C-C-bond,named POF1,POF2,POF3,have been synthesized via Friedel-Crafts reaction.2,4,6-tris(bromomethyl)mesitylene was employed as alkylating agent,with triphenylbenzene,tetraphenylethylene and p-quaterphenyl as the aromatic compounds,respectively.These prepared POFs were used as solid-phase microextraction coating for direct immersion extraction of polycyclic aromatic hydrocarbons(PAHs)and their derivatives(oxygenated-PAH and nitrated-PAHs)in environmental water samples before gas chromatography mass spectrometry(GC/MS).The key factors affecting the extraction efficiency including extraction time,extraction temperature,stirring rate,ionic strength and desorption conditions,were studied.The limits of detection(S/N=3)and limits of quantitation(S/N=10)for the target analytes were in the range of 2.5-24.8 and 7.5-74.4 ng L-1,respectively.The recoveries of spiked samples were in the range of 73.1-112.3%with five times in parallel RSDs less than 13.0%.The proposed method was applied for the simultaneous determination of nine PAHs and their derivatives in water samples,showing good accuracy and reliability.