Urinary metabolite quantification employing 2D NMR spectroscopy.

Area of Science:

• Analytical Chemistry
• Biochemistry
• Spectroscopy

Background:

• Two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy is an emerging technique for metabolite quantification in biological samples.
• Traditional 1D 1H NMR spectra have limitations in resolving and quantifying complex biological mixtures like human urine.

Purpose of the Study:

• To demonstrate the superior quantification of human urinary metabolites using 2D 1H-13C heteronuclear single-quantum correlation (HSQC) NMR compared to 1D 1H NMR.
• To establish the utility of 2D HSQC NMR for metabolite profiling in clinical applications, such as inborn errors of metabolism.

Main Methods:

• Acquisition and analysis of 2D 1H-13C HSQC NMR spectra from human urine at natural abundance.
• Generation of separate calibration curves for individual metabolite signals within the 2D HSQC spectra.
• Comparison of quantitative 2D NMR data with results from gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and enzymatic assays.

Main Results:

• 2D 1H-13C HSQC NMR provided superior quantification of human urinary metabolites compared to 1D 1H NMR.
• Achieved lower limits of detection in the low to mid micromolar range, influenced by the number of methyl groups in the analyte.
• Demonstrated good agreement between 2D NMR quantification and established analytical methods for selected metabolites.

Conclusions:

• 2D 1H-13C HSQC NMR is a powerful and accurate method for quantifying human urinary metabolites.
• The technique is suitable for investigating metabolic profiles, particularly in the context of diseases like inborn errors of metabolism.
• This advanced NMR approach offers a valuable alternative or complement to existing analytical techniques in metabolomics.