Detection Of Volatile Components And Application To Evaluation Of Health

With the development of the modern analysis technology,the demand for the detection of trace amount of volatile components in various types of samples is increasing.Especially in the field of health,the volatile components from biosamples often reveal much more information on the disease and health.Due to the easy collection of non-invasive samples,such as saliva,urine and respiratory gases,it is recently becoming a hot issue to analysis the volatile components from non-invasive samples for the early diagnosis of cancer,diabetes and other diseases.However,the extraction of volatile targets is facing with many challenges and recognized as a very difficult problem in the world,because the sample matrix is very complex in these biosamples and the volatile targets are of many characteristics,such as wide variety,low concentration,low boiling point,easy volatility,strong chemical activity and poor stability.At present,the most common extraction method is the headspace solid-phase microextraction,while it has obvious shortcomings,such as fewer types of extraction needles,and limited detection range due to the small amount of adsorbent and unable to be adjusted.Therefore,how to extract volatile components from complex biosamples and improve the sensitivity of extraction method is still a key and difficult task in the field of analysis.To achieve the objective of assessing human health based on the detection of biomarkers in non-invasive samples,the packed-fiber solid-phase extraction(PFSPE)method in this study coupled with Chromatography or Chromatography-Mass Spectrometry was utilized to analysis multiple targets.In order to achieve efficient collection,the extraction and concentration of volatile components,preparation and characterization of nanofiber materials and their adsorption/desorption properties to the targets were researched.The novel nanofiber materials were selected as adsorbents and the suitable extraction devices was prepared,then the solid-phase extraction method for the trace amount of targets in complex biosamples was developed.The method system was applied to the two aspects:(1)The preparation and extraction of high value-added natural products were studied and the preliminary extraction process of volatile essential oils from onion was carried out;(2)The detection method of disease-related biomarkers in non-invasive samples with chromatographic techniques was applied to a comparative study on the two small cohorts of children with Autism Spectrum Disorder(ASD)and overweight,and some very valuable results on the intervention and treatment of children with ASD and obesity was yielded.The details are as follows:Firstly,the single component polystyrene(PS)and acrylic resin(AR)nanofibers,and composites PS-AR nanofibers were prepared by electrospinning,and were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray diffraction(XRD).The suitable adsorption device were designed and manufactured for the static adsorption of gas components,then the adsorption performance of nanofibers on the volatile organic compounds(VOCs)were probed by selecting the representative targets of ethanol,n-butanol,n-hexane,acetone,ethyl acetate,benzene,toluene,chlorobenzene,anisole and nitrobenzene.The results were shown that the extraction performance of nanofibers on volatile components has remarkable characteristics in the selectivity,thermal desorption,temperature sensitivity and regeneration.Secondly,the nanofiber-assisted headspace solid-phase microextraction was initially established.The novel nanomaterials prepared for the enrichment and transmission medium for the volatile targets was combined with the traditional solid-phase microextraction(SPME)technology,which is PFSPE-assisted SPME.The results displayed the target signal detected increases hundreds of times and creates a more efficient system of sample pre-treatment for the volatile components.Thirdly,for the determination of volatile short-chain fatty acids(SCFAs),the method of PFSPE coupled with Gas Chromatography-Mass Spectrometer(GC-MS)was utilized to analyze urine samples from children with ASD.The result demonstrated that the children with ASD have the higher level of SCFAs.The new method and result provide the research support for the intervention and treatment of children with ASD.Fourthly,the PFSPE-GC/MS method were applied to determine the level of SCFAs in the urinary samples from overweight children aged 4-5 years,and the biomarkers of cortisol and cortisone in the saliva and urine samples were simultaneously detected.The correlation between the targets and body weight,family diet habit was analyzed,which provided the data support and theoretical reference for the control and intervention of children's weight.Fifthly,the adsorption and desorption performance of nanofibers on the Volatile Sulfur Compounds(VSCs)in onion was probed,and the preliminary extraction process of volatile essential oils from onion by nanofibers membrane was conducted,then its antioxidant properties in vitro was studied.Compared with the existing adsorbents,the new method is simple,low-cost and environment-friendly with no harmful residues,and can retain the flavor and function of essential oils.Lastly,the effects of adjustment of the composition and concentration of raw polymers,which were electrospun into nanofibers,on the extraction efficiency of PFSPE were further discussed,and the chloramphenicol was selected as target molecular.A new analytical method based on PFSPE for the determination of chloramphenicol in milk was established.Its results show that the method has the advantages of low cost,short time and small dosage of organic solvents,and the mass processing of 12 samples was realized in experiments which suggested the potential of high-through pre-treatment.This study displays that the technology of PFSPE achieves the efficient concentration and improves the extraction efficiency for volatile components just using a few milligrams of nanofibers and one hundred microliters of eluent.The technology can increase the yield of targets in the field of manufacture,and significantly improve the analyte signal and methodological index in the field of analytical test.Our study has shown that the PFSPE technology can be widely applied to many fields and has high value and potential application to food engineering and nutrition research.