Pdf the fragmentation of unsubstituted and substituted 1phenylselanyl azulenes, as well as of the corresponding selenoxides and. The two mass spectra below correspond to two isomers of c 5h10 o. Ppt mass spectroscopy powerpoint presentation free to. Ion formed by addition or the removal of one or several electrons to or from the sample moleculeselectron impact eims. Lecture notes in eimass spectrometry by torben lund. Table of common fragment ions mz ions mz ions 15 ch3 63 c5h3 a 16 o 65 c5h5 a 17 oh 67 c5h7 18 h2o 69 c5h9 19 f 70 c5h10 26 cn 71 c5h11, c3h7co. These examples do not provide information about the fragmentation mechanisms that cause these patterns. The radical cation that is produced when an electron is knocked out of a neutral closedshell molecule in eims initially possesses a lot of energy. The leading scientist in this field was fred mclafferty who together with frantisek turecek has written a very. For the analytical chemist, a mass spectrum is useful for two applications. The ionized molecule often fragments into smaller ionsradicals. Fragment peaks other than the molecular ion peak is. Thus far, gas chromatographymass spectrometry gcms is the. Mass spectrometry today is an indispensable tool in chemistry and life sciences.
This book is tailored to guide students and professionals as well as novices to mass spectrometry from other fields. Ion fragmentation of small molecules in mass spectrometry. The rearrangement shown above produces an ion with mz58. Briefly description about mass spectroscopy a free powerpoint ppt presentation displayed as a flash slide show on id. Fragmentation patterns in the mass spectra of organic compounds how they arise and how to get information from them. An extremely useful result of ei ionization in particular is a phenomenon known as fragmentation.
Supplemental instruction 1060 hixsonlied student success center 2946624. Mass spectroscopy mass spectroscopy is a technique causing the formation of the gaseous ions with or without fragmentation. Fragmentation mechanisms in electron impact mass spectrometry. Mass spectroscopy is a technique causing the formation of.
Mass spec fragmentation an extremely useful result of ei ionization in particular is a phenomenon known as fragmentation. Chapter 2 fragmentation and interpretation of spectra 2. Mass spectrometry fragmentation patterns chemistry. Provided you have a computer data base of mass spectra, any unknown spectrum can be computer analyzed and simply matched against the data base. Which of the following compounds will give a molecular ion having mz an odd number. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Only the combination of manual interpretation along. The dissociation or fragmentation of ions as it is usually referred to in mass spectrometry yields a fragment ion and a neutral. In a typical eims peaks corresponding to both molecular ion and fragment ions are often seen. Following are examples of compounds listed by functional group, which demonstrate patterns which can be seen in mass spectra of compounds ionized by electron impact ionization.
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