High-throughput quantification of lysophosphatidylcholine by electrospray ionization tandem mass spectrometry.
BACKGROUND
Lysophosphatidylcholine (LPC) has been suggested to play a functional role in various diseases, including atherosclerosis, diabetes, and cancer mediated by LPC-specific G-protein-coupled receptors. Initial studies provided evidence for a potential use of LPC as diagnostic maker. However, existing methodologies are of limited value for a systematic evaluation of LPC species concentrations because of complicated, time-consuming procedures. We describe a methodology based on electrospray ionization tandem mass spectrometry (ESI-MS/MS) applicable for high-throughput LPC quantification.


METHODS
Crude lipid extracts of EDTA-plasma samples were used for direct flow injection analysis. LPC 13:0 and LPC 19:0 were added as internal standards, and the ESI-MS/MS was operated in the parent-scan mode for m/z 184. Quantification was achieved by standard addition. Data processing was highly automated by use of the mass spectrometer software and self-programmed Excel macros.


RESULTS
The calibrators LPC 16:0, LPC 18:0, and LPC 22:0 showed a linear response independent of sample dilution and plasma cholesterol concentration for both internal standards. The within-run imprecision (CV) was 3% for the major and 12% for the minor species, whereas the total imprecision was approximately 12% for the major and 25% for the minor species. The detection limit was <1 micromol/L.


CONCLUSIONS
The developed ESI-MS/MS methodology with an analysis time of 2 min/sample, simple sample preparation, and automated data analysis allows high-throughput quantification of distinct LPC species from plasma samples, which could be a valuable tool for the evaluation of LPC as diagnostic marker.
Liebisch
Gerhard
G
Institut für Klinische Chemie und Laboratoriumsmedizin, Universität Regensburg, D-93042 Regensburg, Germany.
Drobnik
Wolfgang
W
Lieser
Bernd
B
Schmitz
Gerd
G
D002138:Calibration; D006801:Humans; D008244:Lysophosphatidylcholines / Q000097:blood*; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization
D008244:Lysophosphatidylcholines