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Quantitative measurement of 4‐hydroxy tamoxifen in human plasma and mammary tumours by combined gas chromatography/negative chemical ionization mass spectrometry
Author(s) -
Girault J.,
Istin B.,
Fourtillan J. B.
Publication year - 1993
Publication title -
biological mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1052-9306
DOI - 10.1002/bms.1200220706
Subject(s) - mass spectrometry , chromatography , chemistry , chemical ionization , gas chromatography , gas chromatography–mass spectrometry , tamoxifen , ionization , analytical chemistry (journal) , medicine , ion , organic chemistry , cancer , breast cancer
A highly sensitive and specific assay was developed for the quantitative measurement of 4‐hydroxy tamoxifen (4‐OH Tam) at the femtomole level in human plasma and mammary tumours. The drug and deuterated internal standard (4‐OH Tam D 4 ) were measured by gas chromatography/negative chemical ionization mass spectrometry with methane as the reactant gas. The two compounds of interest were isolated from the complex biological matrices using a solid‐phase extraction procedure with Extrelut 1 columns. Soft operating conditions were required to convert 4‐OH Tam to the fluorinated derivatives with pentafluorobenzyl chloride. The mass spectrometer was tuned to monitor the abundant and stable molecular ions at m/z 581 and 585 which were generated in the ion source by an electron capture process. This assay required only 0.5 ml of plasma or 0.5 g of mammary tissue, and the quantification limits of the method were 20 pg ml −1 for the body fluids or 100 pg g −1 for the tissue samples. The very low relative standard deviation and mean percentage error calculated during the different within‐day or day‐to‐day repeatability assays have clearly demonstrated the ruggedness of the technique for routine analysis of 4‐OH Tam.