title: 9- and 10-Nitro-oleic acid do not interfere with the GC-MS quantitative determination of nitrite and nitrate in biological fluids when measured as their pentafluorobenzyl derivatives.
abstract: The nitrated lipids 9-nitro-oleic acid (9-NO(2)-OA) and 10-nitro-oleic acid (10-NO(2)-OA) have been reported to be present in blood of healthy humans. Free and esterified forms of 9-NO(2)-OA and 10-NO(2)-OA have been detected in human plasma at about 600 and 300 nM, respectively. These concentrations are of the same order of magnitude of circulating nitrite. In theory, 9-NO(2)-OA and 10-NO(2)-OA may interfere with the analysis of circulating nitrite and nitrate. In the present study, we investigated a possible interference of 9-NO(2)-OA and 10-NO(2)-OA with the GC-MS method of analysis of nitrite and nitrate involving derivatization by pentafluorobenzyl (PFB) bromide in aqueous acetone at 50 degrees C for 5 min (nitrite) or for 60 min (nitrite and nitrate). Our results show that 9-NO(2)-OA and 10-NO(2)-OA do not interfere with the GC-MS analysis of nitrite and nitrate as PFB derivatives in plasma and phosphate buffered saline when added to these matrices at supraphysiological concentrations of 1-10 microM. Thus, nitrated lipids such as 9-NO(2)-OA and 10-NO(2)-OA can be excluded as potential interfering substances in the GC-MS quantitative determination of nitrite and nitrate as their PFB derivatives.
authors.affiliation: Institut für Klinische Pharmakologie, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, D-30625 Hannover, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Mitschke
authors.forename: Frank-Mathias
authors.initials: FM
authors.lastname: Gutzki
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Tsikas
mesh_terms: D001826:Body Fluids / Q000737:chemistry*; D002021:Buffers; D005464:Fluorobenzenes / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D009566:Nitrates / Q000097:blood*; D009573:Nitrites / Q000097:blood*; D019301:Oleic Acid / Q000737:chemistry / Q000378:metabolism*; D009829:Oleic Acids / Q000737:chemistry / Q000378:metabolism*; D005466:Fluorocarbons
chemical_list: D002021:Buffers; D005464:Fluorobenzenes; D009566:Nitrates; D009573:Nitrites; D019301:Oleic Acid; D009829:Oleic Acids; C521487:10-nitro-oleic acid; C025063:pentafluorobenzyl bromide; D005466:Fluorocarbons