Quantification of leukotriene B 4 in synovial fluid by gas chromatography/tandem mass spectrometry

A procedure for the quantification of leukotriene B 4 (LTB 4 ) in synovial fluid has been developed using gas chromatography/tandem mass spectrometry based on selected reaction monitoring of the elimination of t ‐butyldimethylsilanol from the ions of m/z 431 and 438 in the negative ion chemical ionization mass spectra of the di‐ t ‐butyldimethylsilyl/pentafluorobenzyl derivatives of derivatives of leukotriene B 4 and the internal standard ( 2 H 8 )leukotriene B 4 . The detection limit (∼10 pg ml −1 ) is sufficiently low to permit determination of LTB 4 concentration in the synovial fluid of patients with various arthropathies. Single‐stage mass spectrometry was found not to be selective enough to permit quantification of LTB 4 in synovial fluid.