title: Use of quadrupole GC-MS and ion trap GC-MS-MS for determining 3-hydroxy fatty acids in settled house dust: relation to endotoxin activity.
abstract: Gas chromatography-mass spectrometry (GC-MS) using a quadrupole instrument and GC-tandem MS (GC-MS-MS) using an ion trap instrument were applied to determine 3-hydroxy fatty acids (3-OH FAs) with 10-18 carbon chain lengths, specific components of the endotoxin (lipopolysaccharide, LPS) of Gram-negative bacteria, in 30 house dust samples. The two methods provided similar detection sensitivity for methyl ester/trimethylsilyl derivatives of the 3-OH FAs and allowed these acids to be distinguished from co-eluting 2-OH FA derivatives. The correlation coefficients between endotoxin activity (Limulus test) and the combined amounts of 3-OH C10, 3-OH C12, and 3-OH C14 were 0.60 and 0.61 when using GC-MS and GC-MS-MS, respectively. The superior selectivity of GC-MS-MS was illustrated in analyses of sub-milligram amounts of dust, where the chromatograms achieved by GC-MS were difficult to interpret due to a high background and several closely eluting compounds. GC-MS-MS is therefore preferable to GC-MS for determining 3-OH FAs in minute (sub-milligram) amounts of dust.
authors.affiliation: Department of Infectious Diseases and Medical Microbiology, Section of Bacteriology, University of Lund, S-223 62 Lund, Sweden. Lennart.Larsson@mmb.lu.se
authors.forename: A
authors.initials: A
authors.lastname: Saraf
authors.forename: J H
authors.initials: JH
authors.lastname: Park
authors.forename: D K
authors.initials: DK
authors.lastname: Milton
authors.forename: L
authors.initials: L
authors.lastname: Larsson
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D004731:Endotoxins / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D005227:Fatty Acids / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D006090:Gram-Negative Bacteria; D006801:Humans; D012680:Sensitivity and Specificity
chemical_list: D004731:Endotoxins; D005227:Fatty Acids