Documented workflows
Published software workflows and their original methodological context. Check current software documentation for version-specific changes.
Molecular-formula annotation with SIRIUS and ZODIAC
SIRIUS uses isotope patterns and fragmentation trees to score molecular-formula candidates. ZODIAC adds dataset-level re-ranking by exploiting shared fragments and neutral losses between fragmentation trees, using Bayesian inference and Gibbs sampling to improve formula assignments across related spectra.
- Import centroided spectra or LC-MS runs
Import preprocessed .ms/.mgf/.msp-style spectra or centroided mzML/mzXML runs. SIRIUS 6 can create a project space and perform its built-in LC-MS feature detection/alignment for mzML/mzXML inputs.
- Generate formula candidates with SIRIUS
Use accurate precursor mass, isotope-pattern evidence, and fragmentation trees to score candidate molecular formulas and annotate fragment formulas.
- Apply ZODIAC when dataset-level re-ranking is useful
Use ZODIAC to jointly re-rank formula candidates across a collection of spectra based on shared fragmentation-tree fragments and losses.
- Review formula confidence and ambiguity
Inspect top formula candidates, scores, adduct assumptions, isotope/fragmentation support, and alternative candidates before downstream structural annotation.
Requirements
- Accurate precursor mass and preferably informative MS/MS; isotope-pattern quality improves formula annotation.
Considerations
- Molecular-formula annotation is an intermediate step, not complete structural identification.
- ZODIAC is most useful when processing collections of compounds/spectra because its re-ranking uses relationships across fragmentation trees.
Ludwig M, Nothias L-F, Dührkop K, et al. Database-independent molecular formula annotation using Gibbs sampling through ZODIAC. Nature Machine Intelligence 2, 629–641 (2020).
Read the source methodOverview
SIRIUS is a Java-based small-molecule MS/MS framework integrating local and webservice-backed analysis. Current SIRIUS 6 can import centroided mzML/mzXML runs, perform feature detection/alignment with lcms-align, search spectral libraries by identity or analog similarity, annotate molecular formulas with fragmentation trees and isotope patterns, re-rank formulas with ZODIAC, search structure databases through CSI:FingerID/COSMIC, predict compound classes with CANOPUS, and generate de novo candidates with MSNovelist. GUI, CLI, and API-oriented project-space workflows share a common analysis environment.
What can this tool do?
Common uses
- Import centroided LC-MS mzML/mzXML files and perform feature detection/alignment into a SIRIUS project space.
- Annotate molecular formulas using isotope patterns, fragmentation trees, and optional ZODIAC dataset-level re-ranking.
- Perform identity and analog spectral-library searching, including custom spectral/structure databases.
- Search molecular-structure databases with CSI:FingerID/COSMIC, predict compound classes with CANOPUS, and generate de novo candidates with MSNovelist.
- Export formula, structure and class results while retaining feature identifiers for linking back to the abundance table.
Scientific fit
Primary function
Metabolite annotation and identification
Other functions
Machine learning and prediction, Preprocessing and feature extraction, Reference data and database search, Spectral processing and comparison
Analysis types
Untargeted metabolomics, Metabolite profiling
MS level
MS1, MS/MS
Acquisition
Data-dependent acquisition (DDA), Targeted MS/MS, General or unspecified acquisition
Ion mobility
Ion mobility not required
Data compatibility
Inputs
Mass spectra, Feature or peak table
Outputs
Compound list or annotations, Molecular structures, Human-readable report
Input formats
mzML, MGF, MSP, mzXML
Output formats
CSV or TSV, JSON
Scope and considerations
Designed for
- Molecular-formula and structure-candidate annotation from accurate-mass MS/MS data, including compound-class prediction when exact structures remain uncertain.
Not designed for
- Peptides, polymers, or stereochemical elucidation; SIRIUS is designed primarily for accurate-mass small molecules, usually below about 1000 Da.
Important requirements
- High-mass-accuracy MS and preferably informative MS/MS data; the current documentation recommends mass deviations within about 20 ppm.
- A SIRIUS account/license and internet connection are required for webservice-backed features such as CSI:FingerID, CANOPUS, and MSNovelist; these remain free for academic use under current terms.
Considerations
- Formula, library, class, and structure results represent computational evidence and should be combined with orthogonal evidence and appropriate metabolite-identification confidence levels.
- SIRIUS contains both local open-source analysis and proprietary/webservice-backed functions, so access requirements differ among workflow components.
- DIA spectra require prior deconvolution; the documented default workflow expects centroided, high-accuracy spectra with little chimeric signal.
Education
Learn this tool
External tutorials and workshops collected by Navigator. Entries marked Needs review have not been checked end to end.
Access and documentation
Local features and webservice-backed features have different access and licensing conditions. The official documentation should be checked for the current academic and commercial terms.
From tool to strategy
Strategies using SIRIUS
Evidence and review
Documentation-based editorial pass on 6 September 2026: scope, interpretation limits and practical use reviewed against the linked official documentation and cited literature. Software execution, service availability and developer verification were not assessed.
Core publications
Resource papers, direct updates and tool-specific methods. Selection policy.
- Dührkop K, Fleischauer M, Ludwig M, et al. SIRIUS 4: a rapid tool for turning tandem mass spectra into metabolite structure information. Nat Methods 16, 299-302 (2019). doi:10.1038/s41592-019-0344-8
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Entry history
Changes to this catalogue entry, not the tool's software release history. Acceptance and editorial review are separate.
- 2026-09-08 · Entry update
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