Detection of Exchangeable Protons in NMR Metabolomic Analysis Using AI-Designed Water Irradiation Devoid Pulses

Area of Science:

• Nuclear Magnetic Resonance (NMR) Spectroscopy
• Metabolomics
• Biochemistry

Background:

• Proton NMR (¹H NMR) spectroscopy is crucial for metabolite profiling in biofluids, aiding disease diagnostics.
• Current ¹H NMR methods use solvent suppression, which compromises quantification of analytes with exchangeable protons.
• Accurate quantification of metabolites, especially those with exchangeable protons, remains a challenge in biological samples.

Purpose of the Study:

• To develop novel ¹H NMR techniques for precise metabolite quantification in biofluids.
• To overcome limitations of existing solvent suppression methods that affect exchangeable proton signals.
• To enhance the diagnostic utility of NMR spectroscopy in metabolomics.

Main Methods:

• Development of new water irradiation devoid (WADE) pulses using GENETICS-AI.
• Optimization of a 1D ¹H NOESY sequence for metabolomic applications.
• Application of new techniques to human urine, kidney tissue extract, and plasma samples.

Main Results:

• The WADE technique successfully eliminated water signals while preserving exchangeable proton intensities.
• Accurate quantification of common metabolites was achieved in various biological samples.
• Direct and accurate quantification of urea, typically difficult with standard NMR, was demonstrated.

Conclusions:

• The new WADE pulses and optimized 1D ¹H NOESY sequence offer improved accuracy and reliability for metabolite quantification.
• These advancements are expected to significantly enhance the application of NMR in metabolomic studies of biological fluids.
• The developed techniques hold promise for more precise diagnostics of metabolic disorders and other diseases.