A new method for quantifying prenatal exposure to ethanol by microwave-assisted extraction (MAE) of meconium followed by gas chromatography–mass spectrometry (GC–MS)

Ethanol is a legal and widely available substance. There are health and social consequences associated with its abuse. One of the most important problems is related to alcohol consumption during pregnancy. In fact, prenatal ethanol exposure can be associated with fetal alcohol spectrum disorder (FASD), a term used to describe a wide range of potentially lifelong effects that include physical, mental, behavioral, and learning disabilities. Fatty acid ethyl esters (FAEEs), which are non-oxidative metabolites of ethanol, are currently used as biomarkers of direct ethanol consumption in different matrices, including hair, blood, skin surface, and meconium. Analysis of these compounds in meconium reveals exposure to alcohol during the second and third trimesters of pregnancy. An important finding for evaluation of gestational ethanol exposure is the fact that FAEEs do not cross the placenta. Because they accumulate in the fetal gut from approximately the 20th week of gestation until birth, this provides a wide window of detection of chronic exposure to alcohol. The sum of the concentrations of all the FAEEs, with a cutoff of 2 nmol g −1 or 600 ng g −1 meconium, has been recommended as evidence of maternal alcohol use. We introduce a novel technique to quantify ethyl myristate, ethyl palmitate, ethyl stearate, and their deuterated analogues (as internal standards, IS) in meconium using microwave-assisted extraction (MAE) coupled with gas chromatography–mass spectrometry (GC–MS). Limits of detection and quantification were 50 and 100 ng g −1 for all analytes except ethyl stearate (LOD 100 ng g −1 and LOQ 500 ng g −1 ). Calibration curves were linear from the LOQ to 5000 ng g −1 . The validated method was applied to the analysis of 81 meconium samples. Figure