Characterizing the <i>In Vitro</i> Conversion of Benzene Exposure Urinary Biomarker 6-Hydroxy-2,4-cyclohexadienyl Mercapturic Acid (Pre-PhMA) to Phenyl Mercapturic Acid (PhMA) for Human Biomonitoring Applications

= 0.978) can be used to determine the extent of PhMA formation for a specific treatment pH, improving the ability to compare PhMA results among studies with different analytical methods or to absolute health-based cutoffs such as the biological exposure index. To explain the incomplete PhMA formation, we utilized gas chromatography-mass spectrometry to identify and quantify the formation of benzene as a major byproduct of the acid-derived dehydration of pre-PhMA. Further, base-derived dehydration of pre-PhMA to PhMA was performed to validate the benzene formation mechanism observed with acid dehydration.