Analysis of 18 urinary mercapturic acids by two high-throughput multiplex-LC-MS/MS methods

Area of Science:

• Environmental Chemistry
• Biomarker Discovery
• Analytical Chemistry

Background:

• Mercapturic acids (MAs) are end products of glutathione conjugation with electrophilic compounds.
• MAs serve as valuable biomarkers for exposure to various toxicants.
• Existing methods for MA determination are often time-consuming and costly.

Purpose of the Study:

• To develop and validate multiplexed LC-MS/MS methods for the simultaneous determination of 18 mercapturic acids.
• To establish a time- and cost-efficient analytical workflow for MA quantification.
• To identify potential biomarkers of exposure to toxicants, particularly from tobacco smoke.

Main Methods:

• Development and validation of two liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods.
• Multiplexing of individual MA determination methods into a comprehensive assay.
• Application of validated methods to urine samples from a controlled clinical study involving smokers and non-smokers.

Main Results:

• Validated methods demonstrated excellent robustness, accuracy, and sensitivity.
• A simplified sample cleanup procedure accelerated the analytical workflow.
• Significant increases in 13 MAs were observed in smokers compared to non-smokers, with dose-dependent trends for most analytes.
• Identification of potential biomarkers for nine toxicants present in tobacco smoke.

Conclusions:

• The developed LC-MS/MS assays provide a powerful tool for rapid and reliable quantification of 18 MAs.
• These methods facilitate efficient biomarker discovery in clinical and environmental exposure studies.
• The findings suggest specific MAs as potential biomarkers for assessing exposure to tobacco smoke constituents.