Mixed-mode chromatography/isotope ratio mass spectrometry

Area of Science:

• Analytical Chemistry
• Biochemistry
• Separation Science

Background:

• Liquid chromatography coupled to molecular mass spectrometry (LC/MS) is a long-established technique.
• Liquid chromatography coupled to high-precision isotope ratio mass spectrometry (LC/IRMS) has emerged as a powerful tool since 2004.
• LC/IRMS allows for natural abundance and low enrichment delta(13)C measurements in aqueous mixtures, opening new avenues for isotopic studies in biological molecules.

Purpose of the Study:

• To address challenges in developing LC/IRMS methods, specifically concerning chromatographic separation.
• To investigate the benefits of mixed-mode separations for LC/IRMS applications.
• To provide practical guidance for optimizing high-aqueous separations compatible with LC/IRMS interfaces.

Main Methods:

• Focus on mixed-mode chromatography and stationary phases.
• Optimization of chromatographic parameters including column length, temperature, and mobile phase pH.
• Experimental validation using proteogenic amino acids and nucleosides.

Main Results:

• Mixed-mode stationary phases offer a flexible solution to the constraints imposed by LC/IRMS interface design.
• Manipulating chromatographic parameters can significantly improve high-aqueous separations.
• Successful application of developed methods to important biological molecules like amino acids and nucleosides.

Conclusions:

• Mixed-mode chromatography is a viable strategy for overcoming LC/IRMS interface limitations.
• Optimized chromatographic conditions enhance the accuracy and applicability of LC/IRMS.
• This work provides a practical framework for developing new LC/IRMS-compatible chromatographic methods.