MSAlign: Aligning Molecule and Mass Spectra Foundation Models for Metabolite Identification

Fuente: arXiv
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Main Authors: Krzakala, Paul, Melo, Gabriel, Lançon, Camille, Laclau, Charlotte, Flamary, Rémi, Thévenot, Etienne, d'Alché-Buc, Florence
Format: Preprint
Published: 2026
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author Krzakala, Paul
Melo, Gabriel
Lançon, Camille
Laclau, Charlotte
Flamary, Rémi
Thévenot, Etienne
d'Alché-Buc, Florence
author_facet Krzakala, Paul
Melo, Gabriel
Lançon, Camille
Laclau, Charlotte
Flamary, Rémi
Thévenot, Etienne
d'Alché-Buc, Florence
contents Accurately identifying metabolites i.e. small molecules from mass spectrometry data remains a core challenge in metabolomics, with broad applications in drug discovery, environmental analysis, and clinical research. We address the Molecule Retrieval task, which consists in recovering the chemical structure of a metabolite from its MS/MS spectrum given a set of candidate molecules. While the recent release of benchmark datasets such as MassSpecGym and Spectraverse has considerably accelerated the development of novel machine learning approaches, the complexity of data preprocessing pipelines and the lack of unified implementations make methods and results difficult to reproduce and compare. We make three contributions. First, we propose a unified framework encompassing recent approaches based on representation alignment and contrastive learning. Second, we introduce MSAlign, inspired by multimodal alignment in vision-language models, which learns a shared representation space by aligning two frozen foundation models (DreaMS for mass spectra and ChemBERTa for molecules) through lightweight MLP projections trained with a candidate-based contrastive objective. MSAlign is simple to implement, fast to train and consistently outperforms existing approaches across all benchmarks. Third, we investigate a long-standing evaluation problem: data splitting strategies in molecule retrieval implicitly trade off data leakage against domain shift. We formalize this tension by introducing a quantitative measure of distribution shift, and use it to evaluate splitting strategies in existing benchmarks. All datasets, splits, candidate sets, and a unified implementation of MSAlign and baselines are publicly released to support reproducible research.
format Preprint
id arxiv_https___arxiv_org_abs_2605_19752
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle MSAlign: Aligning Molecule and Mass Spectra Foundation Models for Metabolite Identification
Krzakala, Paul
Melo, Gabriel
Lançon, Camille
Laclau, Charlotte
Flamary, Rémi
Thévenot, Etienne
d'Alché-Buc, Florence
Machine Learning
Accurately identifying metabolites i.e. small molecules from mass spectrometry data remains a core challenge in metabolomics, with broad applications in drug discovery, environmental analysis, and clinical research. We address the Molecule Retrieval task, which consists in recovering the chemical structure of a metabolite from its MS/MS spectrum given a set of candidate molecules. While the recent release of benchmark datasets such as MassSpecGym and Spectraverse has considerably accelerated the development of novel machine learning approaches, the complexity of data preprocessing pipelines and the lack of unified implementations make methods and results difficult to reproduce and compare. We make three contributions. First, we propose a unified framework encompassing recent approaches based on representation alignment and contrastive learning. Second, we introduce MSAlign, inspired by multimodal alignment in vision-language models, which learns a shared representation space by aligning two frozen foundation models (DreaMS for mass spectra and ChemBERTa for molecules) through lightweight MLP projections trained with a candidate-based contrastive objective. MSAlign is simple to implement, fast to train and consistently outperforms existing approaches across all benchmarks. Third, we investigate a long-standing evaluation problem: data splitting strategies in molecule retrieval implicitly trade off data leakage against domain shift. We formalize this tension by introducing a quantitative measure of distribution shift, and use it to evaluate splitting strategies in existing benchmarks. All datasets, splits, candidate sets, and a unified implementation of MSAlign and baselines are publicly released to support reproducible research.
title MSAlign: Aligning Molecule and Mass Spectra Foundation Models for Metabolite Identification
topic Machine Learning
url https://arxiv.org/abs/2605.19752