ISSN:
0030-493X
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Chemical ionization of two 1,4-dihydropyridines, lacidipine and its Z-isomer, and their corresponding pyridines in three different reagent gases and the collision-induced dissociation (CID) of their respective mass-selected protonated molecular ions in the collision energy range 10-200 eV were performed on a multiple quadrupole instrument. The weakness of the Breasted acid NH4+ as a protonating agent is clearly manifested in one of the ammonia positive-ion chemical ionization (CI+) mass spectra which displays the addition ion, [M + NH4]+, as the favoured reaction channel. The stereochemistry of the precursor molecules, the exothermicity of the protonation process and the threshold of certain dissociation channels as a function of the collision energy are among the arguments invoked to explain some of the observed differences between the CI+ mass spectra and the CID data of the different isomers investigated. In an attempt to present a more comprehensive study, some high-performance liquid chromatographic retention times and resolutions are also given.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/oms.1210270315
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