Development And Basic Research On Various Separation Technologies Coupled With Electrospray Ionization Mass Spectrometry

Mass spectrometry (MS) could not only provide high sensitivity and reliabledetection for various samples, but also offer much information about the structureand identity of analytes. Electrospray ionization (ESI) interface, as one of the mostfavorite interfaces, permits the mass spectrometric analysis of large biomolecule withmass up to several hundreds of thousands within the low mass scan range. It has alsobeen proven suitable for the coupling with high performance liquid chromatography(HPLC), capillary electrophoresis (CE) and capillaryelectrochromatography (CEC).In this dissertation, taken ESI as the interface, the effect of buffer compositionon the ionization process was studied systematically, and the expression to describethe relationship between the ESI-MS signal intensity and the buffer pH as well asconcentration was obtained. Through both theoretic deduction and LC-ESI-MS &pCEC-ESI-MS experiments, it was approved that the detection sensitivity ofhyphenated systems could be improved by optimizing the buffer pH andconcentration.In CE-ESI-MS system, parameters that affected the separation and detectionwere studied systematically. In addition, a novel interface was designed, by whichthe applicable buffer system was extended, leading to improved peak shape anddetection sensitivity. With a four-port interface, the hyphenation of pCEC with ESI-MS was achieved,and the effects of various parameters were studied systematically. Under theoptimized conditions, the tryptic digest of cytochrome c was analyzed. Furthermore,for the first time, proteins were analyzed by using pCEC-ESI-MS. To improve thedetection sensitivity, on-line concentration by chromatographic zone-sharpeningeffect and field-enhance sample-stacking effect were developed, and the detectionlimit was reduced by 20 to 100-fold. In addition, the methods of analysis of the chief compositions of thebreviscapini extraction, the melatonin and the sugars of beer by using LC-MS/MSwere developed. Moreover, 2D LC-MS/MS was developed to make a comparativestudy of the proteome of two kinds of leukaemia cells, and 224 and 156 proteinswere identified respectively.