Construction Of Novel Online Solid Phase Extraction Technology And Its Application In Urine Analysis

Polycyclic aromatic hydrocarbons(PAHs)are carcinogenic organic pollutants,which are generated by incomplete combustion of organic compounds and widely exist in the environment.They are widespread environmental pollutants,human beings are exposed to PAHs through inhalation,ingestion and skin contact.Long-term exposure to PAHs leads to the production of reactive oxygen species(ROS),which causes DNA oxidative damage and increases the incidence of respiratory,cardiovascular,immune diseases and cancer.Monohydroxy polycyclic aromatic hydrocarbons(OH-PAHs)in urine are widely recognized as biomarkers for assessing environmental exposure levels of PAHs.8-Hydroxy-2’-deoxyguanosine(8-OHdG)is the most abundant oxidative DNA repair product that was discovered in humans.8-OHdG has been extensively used to reflect the degree of DNA oxidative damage.OH-PAHs and 8-OHdG in urine can be used as biomarkers of oxidative stress and DNA damage caused by environmental exposure to PAHs.However,the complex sample matrix and the low level of target analytes in urine,which poses a challenge to the analysis and detection of urine,and it is urgent to develop a sample pretreatment technique that is effective for purification and enrichment.Online solid phase extraction technology can integrate extraction,enrichment,desorption and injection,and it is a new sample pretreatment technology that has been widely concerned in recent years.In particular,online micro-solid phase extraction(online μ-SPE)and online in-tube solid phase microextraction(online IT-SPME)technology have the advantages of low adsorbent dosage,good enrichment effect,high permeability,low organic solvent consumption,simple preparation and high automation.These methods have been successfully applied in the fields of pesticides,environment,biology and food.The choice of adsorbent is essential to sample preparation technology.Porous(three-dimensional network)micro-nanostructure,large specific surface area,abundant adsorption sites and stable performance of electrospinning materials and electrodeposition composite coating materials are very promising adsorbents.Based on this,two kinds of composite nanomaterials were prepared as adsorbents for the online solid phase extraction technology,which were combined with liquid chromatography-mass spectrometry(LC-MS)for the detection of trace metabolites in urine.The details are as follows:1.A novel polydopamine-modified polystyrene/silica electro spun nanofiber(PS/SiO2@PDA)was successfully prepared as a μ-SPE sorbent by self-polymerization of dopamine and electrospinning technology.Based on this material,an innovative and simple online analytical method(online μ-SPE-LC-MS)was established by coupling LC-MS,which had successfully applied to the determination of monohydroxy polycyclic aromatic hydrocarbons(OH-PAHs)in human urine.PS/SiO2@PDA adsorbent has excellent three-dimensional network structure,high porosity,good stability,hydrophilicity and high extraction capacity.Under optimal experimental conditions,the developed method exhibited a wide linear range(0.03-25 ng mL-1)with a correlation coefficient(R2)greater than 0.9957.The relative standard deviation(RSD)was less than 12.4%and the detection limit(LOD)was in the range of 0.002-0.015 ng mL-1.This method achieves good precision,reproducibility and sensitivity.In addition,the relative recovery was between 79.1%and 108.4%.The method had been successfully applied to the online analysis of PAHs metabolites in human urine with the advantages of simplicity,sensitivity and automation.And the proposed method is expected to be a novel method for evaluating the environmental exposure level of PAHs.2.A novel graphene oxide/poly(3,4-ethylenedioxythiophene)/polypyrrole composite coating(GO/PEDOT/PPy)was successfully prepared on the inner wall of a stainless steel tube by electrochemical deposition,and was used as an online IT-SPME sorbent.The coating had excellent chemical and mechanical stability,high extraction efficiency,good resistance to matrix interference and long service life.Combining the superior performance of the composite coating with the advantages of online analysis,a new online IT-SPME-LC-MS method was developed,and it was firstly applied to the rapid and simultaneous analysis of 8-hydroxy-2’-deoxyguanosine(8-OHdG)and OH-PAHs in human urine.The enrichment factors of 8-OHdG and OH-PAHs were between 30 and 48.Under the optimal conditions,the LOD of the method was between 0.004-0.041 ng mL-1,and a wide linear range(0.05-50 ng mL-1)was obtained,and the correlation coefficient(R2)was greater than 0.9946.In addition,the recovery rate was in the range of 71.6%-109.5%,and the RSD was between 2.3%and 14.6%.The online IT-SPME-LC-MS method had the advantages of low cost,simple operation,sensitivity,rapidity and automation,and it was expected to be a potential method for simultaneous determination of trace 8-OHdG and OH-PAHs in complex biological samples.