Development Of Sample Pretreatment Methods Based On Chemical Derivation And Application Of Liquid Chromatography-mass Spectrometry

Ultra-high performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS)has drawn wide attention in the field of analysis due to its advantages of simple operation,high-throughput detection and wide range of applications,and accurate quantification and quantification of mass spectrometry.In recent years,UHPLC-MS/MS was widely used in life analysis chemistry,food safety and environmental protection and so on.The derivatization method used the derivatization reagent with specific functional groups to react quantitatively with the target analyte to improve the physicochemical properties of the target analyte and enhance the ionization efficiency of the target molecule in mass spectrometry and improve the detection sensitivity.Stable isotope labeling derivatization method solved the shortcoming that the obtained isotope internal standard is typically difficult in the traditional isotope dilution method and more accurate of quantitation than the traditional derivation method.Molecular imprinting and dispersive liquid-liquid microextraction were common sample preparation techniques.Molecularly imprinted polymers have a specific site of target analyte that selectively adsorbs the analyte in the biological sample to reduce matrix interference.Dispersive liquid-liquid microextraction could also extract analytes from biological samples,to a certain extent,reduce matrix interference.In this paper,three novel hyphenated technologies were introduced and used UHPLC-MS/MS to detect monoamine neurotransmitters and their biosynthesis precursors and metabolites in rat brain microdialysate,illegal additive hydroxyproline(Hyp)in dairy products and phytosterols in functional foods and medicinal herbs,respectively.The specific work of this paper is as follows:Chapter One: The progress of UHPLC-MS/MS,chemical derivatization,stable isotope labeling derivatization,dispersive liquid-liquid microextraction and molecular imprinting techniques in sample pretreatment were reviewed.Chapter Two: A highly sensitive and efficient stable isotope labeling derivatization combined with ultrasound-assisted dispersive liquid-liquid microextraction was developed to detect monoamine neurotransmitters and their biosynthesis precursors and metabolites in rat brain microdialysate using UHPLC-MS/MS,and successfully applied to the real sample testing.Chapter Three: A novel magnetic molecularly imprinted polymers(MMIPs)wasprepred by using N-hydroxysuccinimidyl rhodamine B ester(RBS)and Hyp derivate as template.A new procedure of in situ derivatization with MMIPs(ISD-MMIPs)has been developed for the specific extraction of Hyp in dairy products and the detection by UHPLC-MS/MS.Chapter Four: A new pretreatment method of microwave-assisted derivatizationcombined with dual ultrasonic-assisted dispersive liquid-liquid microextraction was developed for the rapid and sensitive determination of phytosterols in functional foods and medicinal herbs by UHPLC-MS/MS.