Noninvasive Sampling And Mass Spectrometry Analysis Of Human Saliva By Solid Phase Microextraction Swab

Human saliva contains a large number of metabolites,chemical residues and environmental exposures related to physiology,pathology,and behavior.Rapid detection of human saliva plays an extremely important role in human health and disease diagnosis,and it is also one of the significant frontier scientific issues.To collect human saliva for clinical examination,medical swab is the most commonly used to place into human mouth for in situ sampling of human saliva,and then the collected saliva are determined by instrumental analysis.Among many instrumental analysis methods,mass spectrometry(MS)is one of the most powerful analytical methods,due to its high sensitivity,high specificity,and fast signal response.The new development of ambient MS has greatly facilitated in situ sampling and rapid analysis of human saliva for different purposes.However,by use of ambient MS,various matrices including inorganic salts,small organic molecules,proteins,and biological particles are found to interfere the detectability of target analytes from raw human saliva.It is urgent to further develop new MS methods that combine in vivo noninvasive sampling,high sensitivity,and selectivity.The aim of this project is to develop a new analytical tool for human saliva analysis.In this new method,one or more solid-phase microextraction(SPME)fibers are inserted into a medical cotton swab to form an SPME swab for direct in vivo sampling of human saliva,and then SPME fiber is coupled with different MS-based approaches for detecting target analytes from human saliva under different conditions.In this study,the properties of cotton ball on SPME swab sampling analytes are studied,including background signal,water absorption,selectivity,and filtration.The effects of different extraction time,different extraction materials,and different numbers of SPME fiber are investigated,and the analytical performances and new features of using different MS-based approaches are compared in this work.SPME swab-MS is also successfully used for qualitative analysis and quantitative detection of residual nicotine in human saliva,providing a new method for environmental exposure analysis.The biomarkers screening of pulpitis-affiliated patients’ salvia is explored using this method,demonstrating a new methodology for disease diagnosis of human oral cavity.The changes of salivary metabolites after ingesting or keeping different foods and drugs are investigated,providing a scientific basis for understanding the physiological effects of food and drugs in human oral cavity.In conclusion,the qualitative analysis and quantitative detection of residual nicotine in human saliva can be achieved by use of the SPME swab.At the same time,potential biomarkers were found in the saliva analysis of patients with pulpitis disease,providing a scientific method for the diagnosis of oral diseases.In addition,Multiple SPME fibers of the same or different types were inserted into the medical swab to extract different types of analytes from oral saliva samples,which not only enhanced the enrichment effect of similar compounds,but also expanded the enrichment range of different types of compounds,providing more possible results of oral metabolite biomarkers.It has been demonstrated that the universal strategy of coupling noninvasive sampling SPME swab with gas/liquid chromatography-mass spectrometry can simultaneously detect oral metabolites and changes in salivary metabolites induced by fenbid and spedifen.Overall,our results show that the SPME swab is safe,non-invasive,and in vivo for sampling of human saliva,and has a highly efficient capacity for extracting target analytes from complex matrices,and can be used to couple with different MS-based approaches for multidimensional analysis of different analytes with different properties.This study will be a promising method for clinical diagnosis,drug analysis,food safety,and environmental health in human saliva in the future.