Gas chromatographic-mass spectrometric assay for 2-methoxyethanol and 2-methoxyacetic acid in human plasma and its application to pharmacokinetic studies

A new assay has been developed for simultaneous measurement of 2-methoxyethanol (ME) and its major toxic metabolite, 2-methoxyacetic acid (MAA) in human blood by gas chromatography-mass spectrometry. Over the concentration range 0.3 to 200 μg mL-1, ME and MAA could be determined with a pooled coefficient of variation (eleven concentrations, six replicate samples) of 6.5% and 8.7%, respectively. The limits of quantification of ME and MAA were 0.19 and 0.05 μg mL-1, respectively. The respective mean (SD) recoveries of ME and MAA were 101.3 (2.6)% and 98.2 (4.9)% (n = 3). A study of the effects of human contact with ME liquid showed that this new method is a specific, sensitive, simple, and reliable method both for the pharmacokinetic studies and for the biological monitoring of occupational exposure to ME.