Sensitive and precise monitoring of phosphatidylethanol in human blood as a biomarker for alcohol intake by ultrasound-assisted dispersive liquid-liquid microextraction combined with liquid chromatography tandem mass spectrometry.

Phosphatidylethanol (PEth) is a special phospholipid that is only formed in the presence of ethanol, and therefore, serves as a promising biomarker for alcohol intake. In this study, a simple, rapid and precise method based on LC-MS/MS combined with ultrasound-assisted dispersive liquid-liquid microextraction was developed and validated for the measurements of PEth (16:0/18:1, 16:0/18:2, 16:0/16:0, and 18:1/18:1) in human blood. The influences of several variables for sample extraction and MS detection were carefully investigated. The extraction efficiencies for all the four PEth species were markedly increased compared with the traditional extractions. A limit of detection below 0.56ngmL-1 was obtained. This high sensitivity makes it possible to monitor various alcohol consumption levels in light to heavy drinkers. Good linearity was obtained for all the analytes without interference from the sample matrix. The imprecisions of the intra-run and total assays were lower than 3.1% and 6.5%, respectively, with an average recovery of 99.87%. In addition, the utility of the method was evaluated in an alcohol intake status study. The results indicate that the developed protocol is simple, precise, and sensitive, and can be easily adapted for objective and reliable assessments of alcohol intake in clinical research.