Date of Award

Fall 12-19-2022

Document Type


Degree Name

Master of Science (MS)


Forensic Science



First Advisor or Mentor

Marta Concheiro-Guisan

Second Reader

Ana Pego

Third Advisor

Justine Pardi


Phosphatidylethanol (PEth) is an alcohol biomarker that provides a longer window of detection than direct alcohol measurement or other common alcohol metabolites, like ethyl glucuronide. PEth has become useful in assessing drinking history, such as for alcohol-withdrawal treatment, organ transplant settings or prenatal alcohol exposure determination. A method was developed and validated to quantify PEth 16:0/18:1 and 16:0/18:2 in whole blood and dried blood spots (DBS) by liquid chromatography tandem mass spectrometry (LC-MS/MS). The whole blood method was applied to 149 samples from pregnant women, elucidating possible prenatal alcohol exposure. Fifty μL whole blood and 12.7 mm whole punches from DBS were extracted in methanol. Chromatographic separation was performed in gradient mode with a reversed phase C5 column. We employed electrospray ionization in negative mode, and 2 MRM transitions were monitored per analyte. The methods were linear from 10-750 ng/mL, with the limits of detection and quantification at the lowest calibrator. Both analytes in both matrices showed acceptable bias (±20%, n=15) and imprecision (< 20%, n=15) at three QC levels (28.5, 100, 590 ng/mL). Process efficiencies were >23%, with most CV < 20% (n=10). Among the authentic cases, 7 samples had detectable levels of PEth 16:0/18:1 and/or 16:0/18:2 at concentrations from < LOQ to 75.5 ng/mL. A sensitive and specific method was developed in whole blood and DBS for PEth 16:0/18:1 and PEth 16:0/18:2.

Available for download on Saturday, December 21, 2024

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