Suppression of ionization and optimization of assay for 3-hydroxy fatty acids in house dust using ion-trap mass spectrometry
(2006) In American Journal of Industrial Medicine 49(4). p.286-295- Abstract
- Background 3-Hydroxy fatty acids (3-OHFAs), components of lipid A of gram-negative bacteria are useful chemical markers of endotoxin. Methods We analyzed 3-OHFAs in house dust as trimethylsilyl (TMS) methyl ester derivatives in the electron impact ionization mode using gas chromatography ion-trap mass spectrometry. Linear calibrations with r > 0.995 were observed for all the 3-OHFA methyl ester external standards. Results Recovery efficiency experiments with house dust demonstrated that accurate quantification requires calibration curves to be subjected to phase separation and solid phase extraction (SPE) because of differing clean-up losses according to chain length of 3-OHFAs. Recovery experiments also demonstrated interference with... (More)
- Background 3-Hydroxy fatty acids (3-OHFAs), components of lipid A of gram-negative bacteria are useful chemical markers of endotoxin. Methods We analyzed 3-OHFAs in house dust as trimethylsilyl (TMS) methyl ester derivatives in the electron impact ionization mode using gas chromatography ion-trap mass spectrometry. Linear calibrations with r > 0.995 were observed for all the 3-OHFA methyl ester external standards. Results Recovery efficiency experiments with house dust demonstrated that accurate quantification requires calibration curves to be subjected to phase separation and solid phase extraction (SPE) because of differing clean-up losses according to chain length of 3-OHFAs. Recovery experiments also demonstrated interference with detection of C16:0 by the ion trap, which may be due to suppression of ionization by a constituent in house dust. Interference was overcome by injecting 1:4 dilutions of derivatized samples. The range of recoveries was 89.3%-111.5%.for 3-OHFAs added to house dust. The reproducibility of injections was high (CV for C14:0 = 2.36%). The limit of detection (LOD) was 0.15 ng/mg for each 3-OHFA. Conclusions The modifications we made included: use of 3-hydroxy C11:0 and C13:0 methyl esters as internal standards, subjecting calibration standards to phase separation and SPE; addition of water to phase separation; addition of 1-pentadecanol as a carrier; injecting 1:4 diluted TMS derivatives of 3-OHFAs; and monitoring both m/z 131 and 133 ions to improve stability of area measurements for product ions. This method of optimization establishes an appropriate technique for quantification of 3-OHFAs in house dust. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/414241
- author
- Alwis, KU ; Larsson, Lennart LU and Milton, DK
- organization
- publishing date
- 2006
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- recovery, GCMSMS, house dust, 3-hydroxy fatty acids, endotoxin, suppression of ionization, efficiency
- in
- American Journal of Industrial Medicine
- volume
- 49
- issue
- 4
- pages
- 286 - 295
- publisher
- John Wiley & Sons Inc.
- external identifiers
-
- wos:000236824900008
- pmid:16550567
- scopus:33646032361
- ISSN
- 0271-3586
- DOI
- 10.1002/ajim.20263
- language
- English
- LU publication?
- yes
- id
- ee116c33-c6d7-4bcf-84ee-8be34c58392e (old id 414241)
- date added to LUP
- 2016-04-01 12:03:03
- date last changed
- 2022-01-26 22:07:18
@article{ee116c33-c6d7-4bcf-84ee-8be34c58392e,
abstract = {{Background 3-Hydroxy fatty acids (3-OHFAs), components of lipid A of gram-negative bacteria are useful chemical markers of endotoxin. Methods We analyzed 3-OHFAs in house dust as trimethylsilyl (TMS) methyl ester derivatives in the electron impact ionization mode using gas chromatography ion-trap mass spectrometry. Linear calibrations with r > 0.995 were observed for all the 3-OHFA methyl ester external standards. Results Recovery efficiency experiments with house dust demonstrated that accurate quantification requires calibration curves to be subjected to phase separation and solid phase extraction (SPE) because of differing clean-up losses according to chain length of 3-OHFAs. Recovery experiments also demonstrated interference with detection of C16:0 by the ion trap, which may be due to suppression of ionization by a constituent in house dust. Interference was overcome by injecting 1:4 dilutions of derivatized samples. The range of recoveries was 89.3%-111.5%.for 3-OHFAs added to house dust. The reproducibility of injections was high (CV for C14:0 = 2.36%). The limit of detection (LOD) was 0.15 ng/mg for each 3-OHFA. Conclusions The modifications we made included: use of 3-hydroxy C11:0 and C13:0 methyl esters as internal standards, subjecting calibration standards to phase separation and SPE; addition of water to phase separation; addition of 1-pentadecanol as a carrier; injecting 1:4 diluted TMS derivatives of 3-OHFAs; and monitoring both m/z 131 and 133 ions to improve stability of area measurements for product ions. This method of optimization establishes an appropriate technique for quantification of 3-OHFAs in house dust.}},
author = {{Alwis, KU and Larsson, Lennart and Milton, DK}},
issn = {{0271-3586}},
keywords = {{recovery; GCMSMS; house dust; 3-hydroxy fatty acids; endotoxin; suppression of ionization; efficiency}},
language = {{eng}},
number = {{4}},
pages = {{286--295}},
publisher = {{John Wiley & Sons Inc.}},
series = {{American Journal of Industrial Medicine}},
title = {{Suppression of ionization and optimization of assay for 3-hydroxy fatty acids in house dust using ion-trap mass spectrometry}},
url = {{http://dx.doi.org/10.1002/ajim.20263}},
doi = {{10.1002/ajim.20263}},
volume = {{49}},
year = {{2006}},
}