Gruenke L D, Waskell L A
Department of Pharmaceutical Chemistry, University of California, San Francisco 94143.
Biomed Environ Mass Spectrom. 1988 Dec;17(6):471-5. doi: 10.1002/bms.1200170610.
A selected ion monitoring gas chromatographic mass spectrometric assay for trifluoroacetic acid was developed for the study of the metabolism of the volatile anesthetic agent halothane by in vitro preparations. The assay uses a headspace sampling technique after formation of methyl esters with dimethyl sulfate and sulfuric acid. Pentafluoropropionic acid proved to be a suitable internal standard, although care is required in the preparation of the calibration standards so that they reflect the composition and treatment of the samples. Contamination of the samples, possibly with trifluoroacetic acid itself, was found to be the primary factor in limiting the sensitivity of the assay for the metabolism of halothane. Generally, trifluoroacetic acid could be determined at levels as low as 1 microM in 50-100 microliters of incubate.
