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

• Published in: Journal of environmental monitoring Vol. 1; no. 2; pp. 163 - 168
• Main Authors: Saraf, A, Park, J H, Milton, D K, Larsson, L
• Format: Journal Article
• Language: English
• Published: England 01.04.1999
• Subjects: Air Pollution, Indoor - analysis; Endotoxins - analysis; Environmental Monitoring - instrumentation; Environmental Monitoring - methods; Fatty Acids - analysis; Gas Chromatography-Mass Spectrometry; Gram-Negative Bacteria; Humans; Sensitivity and Specificity
• ISSN: 1464-0325; 1464-0333
• DOI: 10.1039/a809019j

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.