| Organophosphate esters are constantly spreading in the environment because of their wide application,and it is necessary to test their content because they endanger human health.Due to the large differences in properties of organophosphate compounds,low content in the environmental medium,and much interference,it is difficult for commercial solid-phase microextraction coatings which only cover the scale of polarity to simultaneously extract organophosphate compounds to meet the requirements of detection sensitivity.To solve the above problems,this thesis takes graphene oxide(GO)as a base,strong polar trimethyl phosphate(TMP),medium polar tris(2-chloroethyl)phosphate(TCEP),and the weakly polar triphenyl phosphate(TPhP)as template molecules,acrylamide as the monomer,and ethylene glycol dimethacrylate as the crosslinking agent,and three GO-based surface molecularly imprinted polymer(MIPs)monolithic fibers were successfully prepared in fused silica capillaries,including the graphene oxide-based surface trimethyl phosphate imprinted polymer(TMP-MIPs/GO)monolithic fiber,GO-based surface tri(2-Chloroethyl)phosphate imprinted polymer(TCEP-MIPs/GO)monolithic fiber and GO-based surface triphenyl phosphate imprinted polymer(TPhP-MIPs/GO)monolithic fiber.Compared with solid-phase microextraction fiber coating,these three types of monolithic fibers have the advantages of large extraction capacity and strong selectivity;and compared with molecularly imprinted polymer fibers,they have the characteristics of fast extraction rate and high capacity.According to their optimal extraction modes,the three types of monolithic fibers were assembled to form GO-based surface molecularly imprinted polymer monolithic fiber array(MIPs/GO-FA),which are capable of performing high-capacity,high-throughput and high-selectivity extraction of organophosphate with different polarities at the same time.Besides,by combining this array with gas chromatography-flame photometric detector,an analytical method of determining the content of different polar organophosphate in environmental water samples was established.The method is sensitive,accurate and reproducible.The specific research contents of this paper are as follows:1.Preparation and Characterization of TMP-MIPs/GO,TCEP-MIPs/GO and TPhP-MIPs/GO Monolithic Fibers:First,using strong polar TMP and medium polar TCEP as well as weaker polar TPhP as template molecules.Besides,GO was used as a base,acrylamide was used as the functional monomer,a crosslinking agent and an initiator were added and mixed uniformly to make a pre-polymerization solution.Then the pre-polymerization solution was injected into a quartz capillary tube to thermally initiate polymerization.By removing the outer wall of the quartz capillary tube,TMP-MIPs/GO,TCEP-MIPs/GO and TPhP-MIPs/GO monolithic fibers were obtained respectively.The three monolithic fibers were characterized by Fourier infrared spectroscopy,Raman spectroscopy,atomic force microscopy,transmission electron microscopy,scanning electron microscopy,thermal analyzer and specific surface area analyzer,the results indicated that three molecularly imprinted monolithic fibers with the porous structure and large specific surface area(>650 m2/g)have been successfully prepared.They all have good thermal and chemical stability.2.Study on the adsorption properties of TMP-MIPs/GO,TCEP-MIPs/GO and TPhP-MIPs/GO monolithic fibers:Under the best extraction mode,the changes of the adsorption capacity of the three monolithic fibers to their template molecules with time and concentration were investigated.The adsorption equilibrium time of TMP-MIPs/GO and TPhP-MIPs/GO monolithic fibers was both 50 min,the adsorption equilibrium time of TCEP-MIPs/GO monolithic fibers was 40 min,the adsorption equilibrium time of them were all 10 minutes faster than corresponding molecularly imprinted materials with the same template molecule.These three types of monolithic fibers have a large adsorption capacity for their respective template molecules.For example,the maximum adsorption capacity of TMP-MIPs/GO for TMP was 391 μg/g,the maximum adsorption capacity of TCEP-MIPs/GO for TCEP was 681μg/g,and the maximum adsorption capacity of TPhP-MIPs/GO for TPhP was 7060 μg/g.The extraction selectivity to template molecules of the three types of monolithic fibers was investigated,the results showed that the three types of monolithic fibers all have good selectivity.3.The establishment of analysis method of MIPs/GO-FA solid phase microextraction combined with gas chromatography-flame photometric detector and analysis of actual environmental water samples:The TMP-MIPs/GO,TCEP-MIPs/GO and TPhP-MIPs/GO monolithic fibers were fixed on a stainless steel wire according to their optimal extraction modes,a GO-based surface molecularly imprinted polymer fiber array(MIPs/GO-FA)solid-phase microextraction device was constructed.The extraction conditions of MIPs/GO-FA were optimized,and the MIPs/GO-FA was compared with commercial coating fibers PA and PDMS under optimal conditions.The results showed that MIPs/GO-FA has the best simultaneous extraction effect for TMP,TCEP and TPhP.Under the best conditions,the method of combining MIPs/GO-FA solid phase micro-extraction device with gas chromatography-flame photometric detector was established.Meanwhile,TMP,TCEP and TPhP in environmental water were measured.The results showed that the target analytes had a good linear relationship in the concentrantion range of 0.004-70 ng/mL.The method had a low quantitation limit(0.0017-0.005 ng/mL)and the relative standard deviations of intra-day and inter-day precision were all less than 4.9-8.6%and 5.8-8.2%respectively.And the relative standard deviation of material repeatability between batches within 7.2-9.1%.MIPs/GO-FA was employed for the determination of TMP,TCEP and TPhP in actual water samples,the recovery rate was between 79.4-112.0%.The method has high sensitivity and accuracy,good repeatability.It can be used for the simultaneous analysis and detection of TMP,TCEP and TPhP in environmental water samples. |
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