Mass-analyzed ion kinetic energy spectroscopy

MIKES. mass-analyzed ion kinetic energy spectroscopy... 

Mass-analyzed ion kinetic energy spectroscopy (MIKES). This scan is implemented with reverse-geometry (BE-type) instruments, in which the front-end magnetic sector allows exclusive mass selection of a precursor ion [37], Fragmentation occurs in a region between the two analyzers (second FFR). A scan of the electric sector [Eq. (4.12)] yields a product-ion spectrum. MIKES also allows direct measmement of kinetic-energy release values. 

An improved, three-step synthesis of iV-butyl-l-deoxynojiromycin from D-glucose has been described, involving an enzymic oxidation ofN-butylglucamine. A synthesis ofA/ -[ C]methyl-1-deoxynojirimycin and its manno epimer has been reported in a study of glycosidase inhibition. l,3,4-Trideoxy-3-fluoronojirimycin and its manno epimer have been characterized and stereochemically distinguished by mass-analyzed ion kinetic energy spectroscopy. ... 

Mass analyzed ion kinetic energy scans confirmed the predominant unimolecular loss of CH2=CH2 from the [Ge(CH3)3]+ ion [68]. For reactions of [Ge(CH3)3]+ with organic nucleophiles under the conditions of ion cyclotron resonance spectroscopy, see [65]. 

Of course, the electron-impact source cannot be used if nonvolatile inorganic samples such as metal alloys or ionic residues are to be analyzed. These substances can be investigated using a different kind of ionization chamber called a spark source, similar to the excitation sources used in emission spectroscopy (Chap. 11). The other parts of the spectrometer can be the same as a general-purpose instrument however, a Mattauch-Herzog double-focusing instrument is preferred (Fig. 16.7 below), because the spark source produces ions with a wide spread of kinetic energies. The entire device is known as a spark-source mass spectrometer (SSMS). 

Suitable methods to reveal the surface chemistry of modified materials include X-ray photoelearon spectroscopy (XPS) and time of flight secondary ion mass spectrometry (TOF-SIMS). XPS speara are obtained by irradiating materials with X-ray beams, while simultaneously measuring the kinetic energy and number of electrons escaping from the top 1 to lOnm of the material s surface being analyzed. Qualitative information from the measured chemical shifts allows the identification of surface functionality, quantitative analysis... 

The choice of the ground state of the ion as the final state charged particles is extremely sensitive. Second, the detection of the ions provides mass information, and third, the ionization is always an allowed process. Any molecular state can be ionized, whereas the electronic spectroscopy relies on the existence of optically allowed transitions. Besides this, no Rabi oscillation between bound states, which can interfere with wave packet measurements, can occur in ionization. Further information can be obtained by analyzing the photoelectron (e.g. as to its kinetic energy), analogous to dispersed fluorescence methods. 

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