ISSN:
1052-9306
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Low concentrations of betaxolol in blood plasma and physiological buffers were determined by selected ion monitoring of the intense m/z 72 fragment [CH2=NH—CH(CH3)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 13C, 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.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bms.1200160176
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