Novel Solid-phase Microextraction Coupled With High-performance Liquid Chromatography And Application In Analysis Of Complex Samples

Sample preparation is an important step prior to analysis of complex samples,which directly affects the accuracy,sensitivity and repeatability of the results.Solid phase microextraction(SPME)is a facile and high-efficiency sample preparation technique with low solvent consumption,which has been demonstrated to be suitable for pretreatment of complex samples.In SPME,the properties of extraction material determine the applicability and extraction efficiency of the method.Therefore,one of the most important task in SPME is the development of new,high-efficiency and selective extraction materials.In this work,we aimed to develop new extraction materials for SPME based on deep eutectic solvents,covalent organic frameworks(COFs)and organic polymer monoliths,and applied to the analysis of complex samples by coupling with HPLC.The main contents of this work include four parts:1.Solid phase microextraction with poly(deep eutectic solvent)monolithic column for extraction of nonsteroidal anti-inflammatory drugs:Deep eutectic solvent(DESs)is a new type of green solvent with low toxicity,low cost and ease of preparation.DESs can interact with analytes through multiple interactions.In this part,a DES composed of choline chloride and itaconic acid was synthesized and applied to preparation of polymer monolith inside polydopamine-functionalized poly(ether ether ketone)tube.The monolithic column showed high extraction efficiency to three non-steroidal anti-inflammatory drugs(NSAIDs)with enrichment factors of 98-103.An in-tube SPME-HPLC method based on poly(deep eutectic solvent)monolithic column was developed for determination of three NSAIDs,with low limits of detection of 0.01-0.05 ng/m L.The method was successfully applied to detect NSAIDs in plasma and environmental water samples,with recoveries of 84.5-105.5%and 87.3-113.7%,respectively.2.Preparation of covalent organic framework SNW-1 incorporated monolithic column for in-tube SPME of antiepileptic drugs:SNW-1 is synthesized by terephthalaldehyde and melamine through Schiff base reaction.This material possesses large specific surface area,excellent stability and strong adsorption capacity.The SNW-1incorporated monolithic column was prepared by embedding method and characterized by Fourier transform infrared spectrometry and scanning electron microscope.Owing to the large specific surface area and high adsorption capacity of SNW-1,the extraction efficiency of SNW-1 incorporated monolithic column was significantly improved comparing with the monolithic column without SNW-1.An in-tube SPME-HPLC method based on SNW-1 incorporated monolithic column was developed to extract and detect three antiepileptic drugs in aqueous solution,showing low limits of detection of0.2 ng/m L.This method was applied for the analysis of antiepileptic drugs in plasma samples,recoveries of 88.6-106.1%were obtained.3.Boronate affinity monolithic column incorporated with graphene oxide for in-tube SPME of glycoproteins:Boronate affinity monolithic column incorporated with graphene oxide was prepared by copolymerization of 4-vinylbenzeneboronic acid,ethylene glycol dimethacrylate and graphene oxide in binary porogens.The monolithic column was coupled to a high performance liquid chromatography system for online enrichment and analysis of glycoproteins in aqueous solution.Horseradish peroxidase(HRP)was selected as standard glycoprotein to demonstrate the performance of in-tube SPME-HPLC system.Based on boronate affinity interaction,the developed method can effectively and selectively extract cis-diol containing HRP from the mixture of nonglycoprotein and HRP.Besides,the addition of graphene oxide improved the extraction efficiency of boronate affinity monolith for HRP.The method was also used to analyze rat plasma spiked with HRP,recovery of 95.6%was obtained.4.COF-LZU1-based magnetic sorbent for extraction of polycyclic aromatic hydrocarbons in environmental samples:COF-LZU1 was covalently immobilized onto polyethyleneimine-functionalized magnetic nanoparticles(COF-LZU1@PEI@Fe₃O₄)through the Schiff base reaction between the amino groups of PEI and aldehyde groups of ligand of COF-LZU1.COF-LZU1 can offer strong hydrophobic interaction and?-?stacking interaction with the analytes.Therefore,COF-LZU1@PEI@Fe₃O₄-based extraction method showed high extraction efficiency for polycyclic aromatic hydrocarbons.By coupling with HPLC,the method showed low limits of detection(0.2-20 pg/m L)and good repeatability.The method was successfully applied to the detection of polycyclic aromatic hydrocarbons in environmental water samples and soil samples.