Preparation Of Electrospun Composite Nanofibers And Their Application In Urine Analysis

The composition of urine and its content can reflect the state of entire body at some level,thus the analysis of the urine metabolites is of great significance.In recent years,the morbidity of lung cancer has sharply rised,and it is importance to seek early diagnostic techniques to improve diagnosis and survival.Research has shown that aldehyde metabolites may be the potential biomarkers of lung cancer.Thus,the analysis of aldehydes in unne can provide evidence for seeking the potential biomarkers.Polycyclic aromatic hydrocarbons(PAHs)are widely exist in the atmosphere,and most of them are the environmental cancergens.The human health may be threatened when people are exposed to the PAH polluted environment at long-term.The monitor of PAHs in urine is a way to access the environmental exposure.However,urinalysis encounters the problem of complex sample matrix,low concentration and complicated process.Thus,the development of high selectivity,sensitivity,rapid and simple pretreatment methods becomes an urgent issue to tackle.Thin-film microextraction(TFME)and micro-solid phase extraction(?-SPE)are two novel sample pretreatment methods.TFME has excellent performance such as great extraction rates,short equilibration time and high extraction efficiency.?-SPE has the characteristic of considerable permeability,high extraction capacity and automatic degree.These methods were widely used for different areas including biology,drug,food and environment and so on.The electrospinning nanofibers,as a new kind of adsorbent,have the feature of large specific surface,high porosity and abundant adsorption sites and are widely used in adsorption field.Recently,the development of high extraction efficiency,good selectivity,high sensitivity of adsorbent becomes a research hotspot.In this work,two kinds of nanofibers were fabricated by electrospinning,followed by surface modification,and used as adsorbents of TFME and online-?-SPE,respectively,then the nanofibers-based extraction methods were combined with HPLC and LC-MS for the determination of trace aldehydes and PAHs in human urine.The contents are as follows:1.A novel polydopamine modified polystyrene/graphene electrospun nanofiber membrane(PS/G@PDA)was fabricated as sorbent of TFME by electrospinning and self-polynmerization of dopamine,then the TFME method was combined with HPLC to analyze the aldehydes in urine of lung cancer patients and healthy volunteers.Benefiting from the hydrophilic polydopamine(PDA)coating and the porous fibrous structure,the PS/G@PDA membrane exhibited large surface area,high extraction efficiency,rapid extraction equilibrium,and matrix interference resistance.Several parameters that influence the extraction efficiency were investigated systematically.Under the optimal conditions,the recoveries of the aldehyde compounds varied in the range of 83%-115%,with the relative standard deviation values lower than 14.5%(n=5).Moreover,satisfactory sensitivities with the limits of detection in the range of 2.3-6.5 nmol L-1 and good linearity with excellent correlation coefficients(R2)being larger than 0.9936 had also been achieved.The results demonstrated that the aldehydes in urine were detected successfully and our method was expected to become a promising approach for the determination of trace aldehyde metabolites in complex biological samples.2.The polystyrene@polydopamine-Ag(PS@PDA-Ag)electrospun nanofibers were successfully prepared by electrospinning and surface modification,then a ?-SPE method was developed and combined with LC-MS for online determination of OH-PAHs metabolites in human urine.The novel material displayed desirable hydrophilic,high porosity and good extraction ability.And the online method showed higher automation,desirable enrichment efficiency,better reproducibility,and faster analysis speed when compared with offline manual method.Under the optimal conditions,good linearity(0.02-5 ng mL-1)with excellent correlation coefficients(R2)being larger than 0.9962 had been achieved.The limits of detection were in the range of 0.007-0.032 ng mL-1.Moreover,the RSD values lower than 9.7%and the recoveries of the OH-PAHs among the range of 71-116%were obtained.The results show the online ?-SPE-LC-MS method has the feature of rapidity,sensitivity and automation,and it had the potential to assess the human environmental exposure to PAHs.