🤖 AI Summary
One-dimensional ¹H NMR spectra of complex biological samples often suffer from severe peak overlap and chemical shift variability, which hinder accurate metabolite resolution. This work proposes Bayesian Shift-Invariant Non-negative Matrix Factorization (BSI-NMF), a novel approach that uniquely treats chemical shift variability—traditionally regarded as a nuisance—not as interference but as informative structure. By leveraging experimentally induced shift perturbations, BSI-NMF achieves identifiability of overlapping metabolite signals that are otherwise unrecoverable. Evaluated on simulated data, laboratory-controlled mixtures, and a large-scale real-world dataset comprising 2,439 urine samples from a European cohort, BSI-NMF consistently outperforms existing methods and successfully recovers metabolite signals previously missed by conventional analyses.
📝 Abstract
Overlapping peaks and sample-dependent chemical shift variability prevent reliable metabolite recovery from complex biological spectra. This problem is critical in one-dimensional proton (1D 1H) NMR which has become the standard method providing fast acquisition and information-rich spectra in metabolomics and foodomics. This study demonstrates how chemical shifts can be utilised as a strength in 1D 1H NMR, when suitably modeled through the proposed Bayesian Shift-Invariant Non-negative Matrix Factorization (BSI-NMF) procedure. We find that BSI-NMF accurately recovers the underlying chemical signals in 1D 1H NMR spectra missed by existing analyses approaches across simulations, laboratory created datasets, and a large urine dataset obtained from 2439 people across Europe. Our study highlights how shifts in the chemical signatures - until now perceived as a nuisance - can in fact when suitably modelled be instrumental for unique recovery of metabolites. This creates an opportunity to experimentally induce chemical shifts changes to facilitate unique recovery of spectra.