Unlocking the Bile Acid Universe: Advanced Workflows and a Multidimensional Library of 280 Unique Species

Area of Science:

• Microbiology
• Metabolomics
• Analytical Chemistry

Background:

• Gut microbes and bile acids have a significant impact on host metabolism and immune function.
• Changes in bile acid profiles are linked to various health and disease states.
• Accurate quantification of bile acids is essential but analytically challenging due to co-elution and spectral similarities.

Purpose of the Study:

• To optimize extraction and liquid chromatography-mass spectrometry (LC-MS/MS) parameters for bile acid analysis in biological samples.
• To develop a comprehensive multidimensional reference library for enhanced bile acid identification.
• To improve the differentiation of diverse bile acid species, including conjugated forms.

Main Methods:

• Optimization of extraction protocols for stool, serum, and plasma.
• Comparison of liquid chromatography (LC) conditions and electrospray ionization (ESI) performance.
• Creation of a multidimensional library with LC retention times, ion mobility spectrometry (IMS) collision cross-section (CCS) values, and accurate mass-to-charge ratios for 280 bile acids.
• Utilized ion mobility spectrometry (IMS) as an orthogonal separation technique.

Main Results:

• Established optimal extraction and LC-MS/MS parameters for bile acid analysis.
• Developed a reference library encompassing 280 unique bile acids (endogenous and labeled).
• The library includes retention times, IMS CCS values, and accurate masses, facilitating identification.

Conclusions:

• The developed multidimensional library significantly enhances bile acid identification in complex biological matrices.
• This resource enables more thorough investigations into the biological roles of bile acids and their associations with diseases.
• Improved analytical methods are critical for advancing bile acid research in health and disease.