| Ultra high performance liquid chromatography(UHPLC)is widely used in food industry,pharmaceutical industry,life science research and other fields,because of its fast analysis speed,easy operation,high sensitivity and wide application range.Mass spectrometry(MS)is a method of accurately determining ion by separating the ions(charged atoms,molecules or molecular fragments)by their mass-to-charge ratio in the electric field and the magnetic field.But the quantitative analysis of complex organic compounds has to go through a series of separation and purification operation,is very troublesome.Therefore,the combination of UHPLC and MS is a fast and efficient method for qualitative and quantitative analysis of complex compounds.Derivatization is a commonly used auxiliary pre-treatment technique in chromatographic analysis.The target analytes react quantitatively with the derivatization reagent with specific groups to improve the structure and properties of the analyte.Derivatization has advantages of improving the detection sensitivity and enhancing the ionization efficiency.Dispersive liquid-liquid microextraction(DLLME)is rapid,economical and environmentally benign sample-pretreatment techniques that the micro-upgraded extractant was put into the sample quickly,and then extractant and dispersant-water phase formed extractant beads,greatly expanding the phase contact surface between extractant and water samples,thus extraction equilibrium speed was speed up and the target compounds quickly extracted into the extractant beads.The extraction and enrichment operation has good compatibility with the subsequent detection methods.Thus,the extraction phase can be directly injected into chromatography and so on.In this paper,a rapid,simple ultrasonic assisted in situ derivatization and dispersive liquid-liquid microextraction was developed.High-performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS)was used to detect low-molecular-weight,highly polar analytes such as neurotransmitters,amino acids and endocrine disruptors.In this paper,two new MS sensitive derivatization reagents Lissamine rhodamine B sulfonylchloride(LRSC)and 4’-carbonyl chloride rosamine were designed and synthesized,which significantly improved the detection sensitivity and greatly improved the ionization efficiency.The specific work of this paper is as follows:Chapter One: Introduction of high performance liquid chromatography tandem mass spectrometry,chemical derivatization and dispersive liquid-liquid microextraction.Chapter Two: Determination of dopamine,serotonin,biosynthesis precursors and metabolites in rat brain microdialysates by ultrasonic-assisted in situ derivatization-dispersive liquid-liquid microextraction coupled with UHPLC-MS/MS.Chapter Three: Simultaneous and sensitive determination of 23 estrogens,alkylphenols,bisphenols and parabens in environmental samples and food stuffs by ultrasound-assisted in situ derivatization-dispersive liquid-liquid microextraction combined with UHPLC-MS/MS.Chapter Four: In vivo microdialysis monitoring of multiple amino acids and neurotransmitters in brain from lipopolysaccharide introduced depressive-like behavior rats using ultrasound-assisted in situ derivatization-dispersive liquid-liquid microextraction combined with UHPLC-MS/MS. |
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