Preparation Of Functionalized Graphene/phenolic Resin Adsorbent And Its Application In Complex Sample Preparation

Biological sample analysis is closely related to human health and involves many aspects of human health,such as food and drug safety analysis,disease prediction and diagnosis.Due to the complexity of biological sample matrices,existence of many interfering substances,and trace levels of the target components,biological samples cannot be directly detected by detection instruments even though a variety of detection techniques have been developed,such as spectrum,chromatography,and chromatography-mass spectrometry.Biological samples often need a series of sample preparation operations such as extraction,separation,enrichment,and purification before detection,and the time required for the sample preparation is about 50–70% of the entire analytical work.Therefore,the sample preparation is the key to achieve selective,rapid,and accurate determination of trace target components in biological samples.In biological sample analysis,most sample preparation techniques are established based on adsorbent and sample preparation method.The adsorbent performance affects the extraction efficiency,enrichment ability,and anti-interference ability of the analytical method.And the choice of sample preparation method affects the accuracy,speed,and reproducibility of the analytical method.Therefore,aiming at solving the bottlenecks of adsorbents and sample preparation methods in the field of biological sample preparation,this paper is devoted to synthesizing new adsorbents which have multiple adsorption interactions,fast mass transfer rate,high adsorption capacity,and high selectivity and developing new sample preparation methods which have simplicity,speediness,low consumption of adsorbent,and low cost.And then further combination of the advantages of the new adsorbents and sample preparation methods was made to establish seven extraction and determination methods,which are optimized and evaluated by taking a series of biological samples and compounds as examples.The main results are as follows:Aiming at solving the problems of current adsorbents(single adsorption interaction,low adsorption capacity,and poor selectivity)in the field of biological sample preapation,two new types of adsorbents(functionalized graphene and phenolic resin)have been developed.Functionalized graphene adsorbents: Graphene oxide was modified with ionic liquid,poly(ionic liquid),poly(deep eutectic solvent),and molecularly imprinted polymer through thiol-ene click reaction or reversible-addition fragmentation chain-transfer polymerization to synthesize a series of functionalized graphene adsorbents,which had multiple adsorption interactions,fast mass transfer rate,high adsorption capacity,and high selectivity.Phenolic resin: The resin was prepared into core-shell structure or open channel structure to improve its specific surface area and combined with molecular imprinting technology to improve its selectivity.And further exploration for new low-toxic phenolic monomers and aldehyde crosslinkers was conducted to synthesize a series of phenolic resin adsorbents with excellent adsorption performance,large specific surface area,and good biocompatibility.Choosing typical compounds in biological samples(such as plant growth regulator,veterinary drug,bioactive compound,biomarker,and protein)as analytes to evaluate the adsorption performance of the two new types of adsorbents(functionalized graphene and phenolic resin).The adsorption interactions and mechanism of the adsorbents were analyzed and discussed from static adsorption(Langmuir,Freundlich,and Tempkin isotherm models),adsorption kinetics(pseudo-first-order,pseudo-second-order,intraparticle diffusion models),comparison with commercial adsorbents,etc.The adsorption experimental data showed that the two new types of adsorbents had multiple adsorption interactions,high adsorption capacity,fast mass transfer rate,and high selectivity,which have the potential to be applied for extraction of trace target compounds from complex biological samples.Aiming at solving the problems of current sample preparation methods(high consumption of adsorbent,tedious operation,and high cost),a series of new sample preparation methods have been developed:(1)two miniaturized sample preparation methods(pipette tip solid-phase extraction and infusion needle solid-phase extraction method)were developed by using small-diameter pipette tip or disposable venous infusion needle instead of traditional solid-phase extraction catridge for reducing the consumption of adsorbent and cost of the method;(2)a rapid filter solid-phase extraction method was developed by refitting removable filter and connecting with a syringe instead of traditional solid-phase extraction device for improving the speed and work efficiency of the analytical method;(3)Based on the previous works,a new method ultrasonic-assisted dispersive-filter extraction method with low consumption of adsorbent,low cost,and easy operation was further developed by combining the advantages of dispersive solid-phase extraction(rapid adsorption and elution)and filter solid-phase extraction(rapid separation).Aiming at the current difficulties and hot issues in the field of biological sample analysis,seven new extraction and determination methods were developed by the combination of the advantages of the new functionalized graphene/phenolic resin adsorbents(multiple adsorption interactions,high adsorption capacity,fast mass transfer rate,and high selectivity)and sample preparation methods(low consumption of adsorbent,simple and fast operation,and low cost).And a series of compounds in biological samples(such as ?-agonists in swine urine,biomarkers in human urine,anticancer active substance in broccoli,plant growth regulators in fruit and vegetable)were chosen as examples for investigating the application of the proposed methods.After optimization and evaluation of a series of extraction parameters and methodological parameters,these methods have been successfully applied to rapid,accurate,and selective determination of trace target analytes in complex biological samples,which provided practical solutions for solving the problems in the analysis of complex biological samples.