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Selected ion monitoring of metoprolol and two metabolites in plasma and urine using deuterated internal standards
Author(s) -
Ervik Magnar,
Hoffmann KurtJürgen,
KylbergHanssen Kerstin
Publication year - 1981
Publication title -
biomedical mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0306-042X
DOI - 10.1002/bms.1200080708
Subject(s) - metoprolol , urine , chemistry , deuterium , chromatography , plasma , ion , medicine , biochemistry , physics , atomic physics , nuclear physics , organic chemistry
A highly sensitive and specific quantitative assay for metoprolol and two of its metabolites, containing an unchanged 2‐hydroxy‐4‐isopropylaminopropoxy sidechain, has been developed. The compounds are isolated from the alkalized sample (plasma or urine) by extraction with dichloromethane, and converted to trifluoroacetyl derivatives by reaction with methyl‐bis‐(trifluoroacetamide). The reaction mixture is gas chromatographed on an OV‐17 column and each substance is assayed by electron impact mass spectrometry using selected ion monitoring, and quantified by comparing the intensity of fragment ion m / z 266 with the intensities of corresponding fragment ions from the deuterated internal standards ( m / z 270 and 271). It is possible to determine concentrations as low as 1 nmol I −1 (0.3 ng ml −1 ) in 1 ml of sample with a relative standard deviation of less than 10%.