Premium
Determination of the β‐blocker betaxolol and labelled analogues by gas chromatography/mass spectrometry with selected ion monitoring of the α‐cleavage fragment ( m / z 72)
Author(s) -
Lee C. R.,
Coste A. C.,
Allen J.
Publication year - 1988
Publication title -
biomedical and environmental mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0887-6134
DOI - 10.1002/bms.1200160176
Subject(s) - betaxolol , chemistry , mass spectrometry , chromatography , resolution (logic) , trimethylsilyl , ion , electron ionization , selected ion monitoring , gas chromatography , analytical chemistry (journal) , ionization , gas chromatography–mass spectrometry , medicinal chemistry , organic chemistry , medicine , timolol , intraocular pressure , artificial intelligence , computer science , ophthalmology
Low concentrations of betaxolol in blood plasma and physiological buffers were determined by selected ion monitoring of the intense m / z 72 fragment [CH 2 NHCH(CH 3 ) 2 ] + formed by electron impact ionization of the O ‐trimethylsilyl derivative. At a mass spectrometric resolution of 3000, fewer potentially interfering peaks were seen than at low resolution. There remained a chemical interference, corresponding to 100 pg/sample, which arose during treatment of the samples. This method is more sensitive than previous ones, but it is restricted to situations where the specificity can be controlled. When the m / z 72 fragment was mass‐shifted by using betaxolol appropriately labelled with deuterium or 13 C, both the interference and the baseline noise were greatly reduced; concentrations of labelled betaxolol as low as 10–20 pg/sample can be determined with little difficulty.