Selective detection of phosphatidylethanol homologues in blood as biomarkers for alcohol consumption by LC-ESI-MS/MS.
A new validated method for the quantitation of the abnormal phospholipid phosphatidylethanol (PEth)--a biomarker for ethanol uptake--has been developed by LC-ESI-MS/MS following miniaturised organic solvent extraction and reversed phase chromatography with phosphatidylbutanol (PBut) as internal standard. PEth homologues with two fatty acid substituents-PEth 18:1/18:1, PEth 16:0/16:0-were determined in post-mortem blood collected from heavy drinkers at autopsy and also in whole blood samples from a volunteer after a single 60 g-dose of ethanol. Furthermore, PEth 18:1/16:0 or its isobaric isomer PEth-16:0/18:1 was detected. In comparison to previous high-performance liquid chromatography (HPLC) methods with evaporative light scattering detection (ELSD), the LC-MS/MS-method is more sensitive--with a limit of detection below 20 ng/ml--and more selective for single PEth homologues, while ELSD has been used for detection of the sum of PEth homologues with approximately 10 times less sensitivity. LC-MS/MS enables monitoring of PEth homologues as biomarkers for harmful and prolonged alcohol consumption as with HPLC/ELSD earlier, where PEth is measurable in blood only after more than 50 g ethanol daily intake for more than 2 weeks. Because of its higher sensitivity, there is a potential to detect single heavy drinking by LC-MS/MS, when PEth is formed in very low concentrations. This opens a new field of application of PEth to uncover single or multiple heavy drinking at a lower frequency and with a larger window of detection in blood than before by HPLC/ELSD or by use of other direct markers, e.g. ethyl glucuronide or ethyl sulfate.
Gnann
H
H
Institute of Legal Medicine, University Medical Centre, Albertstrasse 9, 79104 Freiburg, Germany.
Weinmann
W
W
Engelmann
C
C
Wurst
F M
FM
Skopp
G
G
Winkler
M
M
Thierauf
A
A
Auwärter
V
V
Dresen
S
S
Ferreirós Bouzas
N
N
D000428:Alcohol Drinking / Q000097:blood*; D053000:Analytic Sample Preparation Methods / Q000379:methods*; D015415:Biomarkers / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D000431:Ethanol / Q000097:blood; D005227:Fatty Acids / Q000032:analysis; D020404:Glycerophospholipids / Q000097:blood* / Q000737:chemistry; D006801:Humans; D008832:Microchemistry; D015394:Molecular Structure; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization; D015813:Substance Abuse Detection / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
D015415:Biomarkers; D005227:Fatty Acids; D020404:Glycerophospholipids; C051521:phosphatidylethanol; D000431:Ethanol