Levels of methyleugenol in a subset of adults in the general US populationas determined by high resolution mass spectrometry

We developed a sensitive and accurate analytical method for quantifying met hyleugenol (ME) in human serum. Our method uses a simple solid-phase extrac tion followed by a highly specific analysis using isotope dilution gas chro marography-high resolution mass spectrometry. Our method is very accurate; its limit of detection is 3.1 pg/g and its average coefficient of variation is 14% over a 200-pg/g range. We applied this method to measure serum ME c oncentrations in adults in the general U.S. population. ME was detected in 98% of our samples, with a mean ME concentration of 24 pg/g (range < 3.1-39 0 pg/g). Lipid adjustment of the data did not alter the distribution. Bivar iate and multivariate analyses using selected demographic variables showed only marginal relationships between race/ethnicity and sex/fasting status w ith serum ME concentrations. Although no demographic variable was a good pr edictor of ME exposure or dose, our data indicate prevalent exposure of U.S . adults to ME. Detailed pharmacokinetic studies are required to determine the relationship between ME intake and human serum ME concentrations.