Quantitative gas chromatography-mass spectrometry analysis of leukotriene B4.

Publisher Summary The chapter presents a study on analysis of leukotriene B 4 by quantitative gas chromatography-mass spectrometry (GC-MS). The chapter describes a GC-NCI (negative-ion chemical ionization)-MS assay for LTB 4 employing [ 2 H 4 ] LTB 4 as an internal standard, which is both sensitive and selective for quantifying LTB 4 in biological matrixes. To give LTB 4 suitable electron capture and chromatographic properties necessary for GC-NCI-MS, the pentafluorobenzyl (PFB) ester of the carboxylic acid and the trimethylsilyl (TMS) ethers of the alcoholic hydroxyl groups of LTB 4 are formed. The GC-MS assay for LTB 4 described here is based on GC-NCI-MS of the pentafluorobenzyl (PFB), trimethylsilyl (TMS) derivative of LTB 4 with selected-ion monitoring using a stable isotope analog of LTB 4 as an internal standard. The general steps are as follows: (1) addition of the [ 2 H 4 ]LTB 4 internal standard to the sample, (2) partial purification of the sample, (3) formation of the PFB ester of the carboxylic acid group of LTB 4 , (4) purification by silicic acid chromatography, (5) silylation of the alcohol hydroxyls of LTB 4 , (6) determination of the ratio of unlabeled to labeled LTB 4 internal standard by selected-ion monitoring GC-MS.