ISSN:
0951-4198
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
The formation of deprotonated molecules, [M - H]-, of α-tocopherol under fast-atom bombardment (FAB) conditions has been discussed on the basis of a proton subtraction reaction between analyte and matrix molecules. The use of proton-accepting matrices such as diethanolamine (DEA) and pentamethyleneglycol (PMG) gave higher intensities of the [M - H]- ion and more definitive spectral data than when other matrices, a 1:2 (v/v) mixture of thioglycerol (TG) and dithiothreitol (DTT), or m-nitrobenzylalcohol (m-NBA), were used. The order of proton acceptability evaluated for the matrices used was DEA〉PMG〉DTT〉m-NBA. It was concluded that the proton acceptability, which is measured by gas-phase basicity or proton affinity, is a most important factor for the formation of both [M + H]+ and [M - H]- ions under FAB conditions. Further, the formation of molecular ions, M+·, under FAB conditions and the formation of [M - H]- ions by electron impact have been discussed by using α-tocopherol.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/rcm.1290080405
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