Non-hydrogenative para-hydrogen-induced polarization (nhPHIP) has proven a powerful tool for the enhanced NMR detection of several classes of metabolites in complex mixtures. Particularly, compounds carrying an α-amino acid motif have been previously detected and quantified in biological samples and natural extracts at submicromolar concentrations using 2D nhPHIP NMR spectroscopy. This technique is here applied for the first time in a semi-targeted metabolomics NMR study on urine from patients suffering from Pyridoxine-Dependent Epilepsy (PDE), currently diagnosed by the presence of dilute unique biomarkers. The signal enhancement, combined with the resolving power of 2D nhPHIP, results in a superior sensitivity to the metabolic composition compared to conventional 1H NMR, demonstrating its potential in NMR-based metabolomics.
Posthumus et al. (Tue,) studied this question.