| Summary: | 碩士 === 淡江大學 === 化學學系 === 87 === 2.Electron Capture Detection Mass Spectrometry is a sensitive and selective technique for the analysis of compounds containing electrophilic functional groups.
It has been used extensively for the analysis of many classes of compounds in the traditional mass spectrometers but none was reported from the ion trap mass spectrometer since the traditional ion trap MS can not perform negative ion analysis. However, in this study we have examined a series of Phthalic anhydride and their derivatives by electron capture detection in the ion trap tandem mass spectrometers with an external source (the Finnigan GCQplus). The GCQ is the first commercial benchtop ion trap mass spectrometer with the capability to perform negative ion analysis.
In this study, a series of halogenated Phthalic anhydride and their derivatives will be examined. Methane was used as the reagent gas. Since these halogenated compounds possess higher electron affinities, negative ions can be formed perdominantly through a resonance electron capture process. Besides, using the tandem in time ion trap mass spectrometry can select a specific m/z of ion to perform MS/MS. Then the selected precursor ions dissociate by the collisional activation technique. From the fragments of parent ion, the structure of ions can be determined. These noval experiments can provide valuable results for negative ions which could not be detected by an traditional internal ionization ion trap mass spectrometer in the past.
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