Analysis of Dihydropyridine Calcium Channel Blockers Using Negative Ion Photoionization Mass Spectrometry

The fragmentation of dihydropyridine calcium-channel antagonists are compared by electrospray ionization (ESI) and atmospheric pressure photonization (APPI). The results demonstrate that in ESI the preferred ionization process is in positive mode, with the mass spectra of [M+H]+ showing base peak io...

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Bibliographic Details
Published in:Journal of chromatographic science 2008-01, Vol.46 (1), p.35-41
Main Authors: Pereira, Alberto S., Bicalho, Beatriz, Ilha, Jaime O., De Nucci, Gilberto
Format: Article
Language:English
Subjects:
Analysis
Biological and medical sciences
Calcium Channel Blockers - analysis
Calcium Channel Blockers - chemistry
Dihydropyridines - analysis
Dihydropyridines - chemistry
General pharmacology
Mass Spectrometry - methods
Medical sciences
Molecular Structure
Pharmacology. Drug treatments
Reproducibility of Results
Spectrometry, Mass, Electrospray Ionization - methods
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Summary:The fragmentation of dihydropyridine calcium-channel antagonists are compared by electrospray ionization (ESI) and atmospheric pressure photonization (APPI). The results demonstrate that in ESI the preferred ionization process is in positive mode, with the mass spectra of [M+H]+ showing base peak ions probably formed by loss of alcohols from carboxyl groups. Conversely, in APPI, a high intense peak is observed in negative mode due to deprotonated molecule [M-H]- after two serial 1, 2-hydride shifts leading to a rearranged deprotonated molecule [M-H]-. These ions undergo another 1,2-hydride shifts to produce a nitro-phenyl product ion of m/z 122. The APPI is also used to develop a method for the quantitation of dihydropyridines (e.g., nifedipine) in human plasma.
ISSN:0021-9665
1945-239X
DOI:10.1093/chromsci/46.1.35