• You can download some sample spectra from the SIRIUS website.
  • To get started quickly you may also want to have a look at our video tutorials.
  • To process a full LC-MS/MS run, you can also use your own .mzML files and run the following examples. This will perform features detection first. Also, annotating 100s or 1000s features may take a while.

Graphical User Interface

Analyzing multiple compounds

SIRIUS’s “Batch mode” corresponds to analyzing many compounds at once, each having one or more mass spectra. Obviously, you can also use this workflow to analyze a single compound.

Foo
Analyze multiple compounds in a view simple steps. Steps in figure do not directly correspond to detailed steps below.
  1. Move the files demo-data/ms/Bicuculline.ms and demo-data/ms/Kaempferol.ms and from the demo data via Drag and Drop into the application window.

  2. The two compounds are now displayed in the compound list.

  3. Check if the ionization and parent mass is correctly annotated.

  4. Click on the Compute All button.

  5. Select SIRIUS.

  6. Change the instrument type as well as the maximal allowed mass deviation. Be aware that this settings will be used for all imported compounds.
  7. Check if the currently selected molecular molecular formula generation strategy aligns with your research question.

  8. Select Predict Properties & CANOPUS to predict the compounds’ molecular fingerprints with CSI:FingerID as well as their compound classes with CANOPUS.
  9. Select CSI:FingerID structure database search to search compounds in a structure database with CSI:FingerID.
  10. Click Compute.

  11. A gear symbol occurs on the lower right corner of each compound. This means that the compound is part of a computation job.

  12. Sometimes a computation might take a long time (e.g. for compounds with a lot of elements or very high masses). You can cancel running computations by selecting Cancel All in the toolbar.

  13. Inspect results with the help of the Formulas, Structure and Compound Classes views. Even more details can be found by looking at the Substructure Annotation and Predicted Fingerprint views.

Command Line Interface

The demo-data contains examples for three different data formats readable by SIRIUS.

Example 1: MGF file

The MGF folder contains an example for a MGF file containing a single compound with several MS/MS spectra measured on an Orbitrap instrument. SIRIUS recognizes that these MS/MS spectra belong to the same compound because they have the same parent mass. To analyze this compound, run:

sirius --input demo-data/mgf/laudanosine.mgf --output <output.sirius> formula -p orbitrap fingerprint compound-classes structure write-summaries --output <summary-files-dir>

This command runs 4 subtools at once: formula annotation, molecular fingerprint prediction, compound class annotation and structure database search.

The formula_candidates.tsv in <summary-files-dir>/0_laudanosine_FEATURE1 should look similar to this:

rank	molecularFormula	adduct	precursorFormula	SiriusScore	TreeScore	IsotopeScore	numExplainedPeaks	explainedIntensity	medianMassErrorFragmentPeaks(ppm)	medianAbsoluteMassErrorFragmentPeaks(ppm)	massErrorPrecursor(ppm)	lipidClass
1	C21H27NO4	[M + H]+	C21H27NO4	24.65417225757305	16.673823307501223	7.98034895007183	10	0.9945969759520045	0.007637492516338191	0.4982304820065859	0.7071154657093854	
2	C19H29NO4	[M + Na]+	C19H29NO4	21.14569419257409	15.328042039004671	5.817652153569419	10	0.9945969759520045	0.8982080585874639	1.2778688586195766	7.423133528795216	
3	C17H23N7O2	[M + H]+	C17H23N7O2	19.270167038174378	14.209441689860592	5.060725348313786	10	0.9945969759520045	0.8982080585874639	1.2778688586195766	8.203923029468156	
4	C15H28N5O3P	[M + H]+	C15H28N5O3P	18.874745611339133	13.87676301554373	4.997982595795404	10	0.9945969759520045	0.8982080585874639	1.2778688586195766	3.5880578691669838	
5	C19H25N4O3	[M + H]+	C19H25N4O3	18.047443230086564	10.915836537157713	7.131606692928852	9	0.9900893988366646	-0.01690518911597119	0.6982192702970249	4.455519247668116	
6	C17H29N5O	[M + K]+	C17H29N5O	15.00462580213599	14.724156079206512	0.28046972292947725	11	0.9999999999999998	-1.461376225764996	2.4522252659018866	3.2647482579632285	
7	C17H30N2O4P	[M + H]+	C17H30N2O4P	14.662475232609417	8.064939679043038	6.597535553566379	9	0.9888793275025645	-0.28967448264108003	0.9201704555380266	-0.1603459126330561	
8	C13H33N3O4P2	[M + H]+	C13H33N3O4P2	14.270528279509012	11.207732656567146	3.0627956229418665	10	0.9945969759520047	-0.4982304820065859	1.2778688586195766	-1.0278072909754976	
9	C19H31N2O2	[M + K]+	C19H31N2O2	11.942179098282763	10.62247877626541	1.3197003220173515	10	0.9945969759520045	-2.150500852166065	2.150500852166065	-0.48365552383681126	
10	C15H34N3O2P	[M + K]+	C15H34N3O2P	11.940863632556848	11.940863632556848	0.0	10	0.9945969759520045	-2.2458900015019885	2.2458900015019885	-1.351116902337944	

This is a ranking list of the top molecular formula candidates. The best candidate is C21H27NO4 with an overall score (SiriusScore) of 24.654. This score is the sum of the TreeScore (16.674) and the IsotopeScore (7.980).

The rear columns contain the number of explained peaks in MS/MS spectrum as well as the relative amount of explained intensity. The latter value should usually be over 80 % or even 90 %. If this value is very low you either have strange high intensive noise in your spectrum, or the allowed mass deviation might be too low to explain all the peaks.

The structure_candidates.tsv in <summary-files-dir>/0_laudanosine_FEATURE1 should be similar to this (trunctated version):

rank	formulaRank	ConfidenceScore	CSI:FingerIDScore	molecularFormula	adduct	InChIkey2D	InChI	name	smiles
1	1	0.8708826550014862	-3.262869483152835	C21H27NO4	[M + H]+	KGPAYJZAMGEDIQ	InChI=1S/C21H27NO4/c1-22-9-8-15-12-20(25-4)21(26-5)13-16(15)17(22)10-14-6-7-18(23-2)19(11-14)24-3/h6-7,11-13,17H,8-10H2,1-5H3	Laudanosine	CN1CCC2=CC(=C(C=C2C1CC3=CC(=C(C=C3)OC)OC)OC)OC
2	1	N/A	-86.96508835580653	C21H27NO4	[M + H]+	VDGYRASFPNRLPJ	InChI=1S/C21H27NO4/c1-22(2)9-8-15-12-18(23)20(25-4)13-16(15)17(22)10-14-6-7-19(24-3)21(11-14)26-5/h6-7,11-13,17H,8-10H2,1-5H3/p+1	1-[(3,4-dimethoxyphenyl)methyl]-7-methoxy-2,2-dimethyl-3,4-dihydro-1H-isoquinolin-2-ium-6-ol	C[N+]1(CCC2=CC(=C(C=C2C1CC3=CC(=C(C=C3)OC)OC)OC)O)C
3	1	N/A	-102.18328682988958	C21H27NO4	[M + H]+	VHLMUHYXPXECPC	InChI=1S/C21H27NO4/c1-22(2)9-8-15-12-20(25-4)21(26-5)13-16(15)17(22)10-14-6-7-19(24-3)18(23)11-14/h6-7,11-13,17H,8-10H2,1-5H3/p+1	null	C[N+]1(CCC2=CC(=C(C=C2C1CC3=CC(=C(C=C3)OC)O)OC)OC)C
4	1	N/A	-224.48821737216022	C21H27NO4	[M + H]+	ILJTXKNIYLUOKP	InChI=1S/C21H27NO4/c1-14-18(23-2)7-6-16(21(14)26-5)12-22-9-8-15-10-19(24-3)20(25-4)11-17(15)13-22/h6-7,10-11H,8-9,12-13H2,1-5H3	Oprea1_099380	CC1=C(C=CC(=C1OC)CN2CCC3=CC(=C(C=C3C2)OC)OC)OC
...

This is a ranking of the top structure candidates. The best hit has a confidence score telling you how certain this prediction is correct. Each structure hit also has a formulaRank since a compound may have different molecular formula candidates. The file contains all structure information (InChI, SMILES) and also structure database IDs (not shown here).

The formula_identifications.tsv and compound_identifications.tsv in <summary-files-dir> contain similar information but only for the top hit of each analyzed compound. The formula_identifications_adduct.tsv and compound_identifications_adduct.tsv contain this information for each possible adduct of each compound.

If you want to look at the fragmentation trees, structures or compound classes visually, you can open the output (<outputdir>) in the GUI and use the included Tree view tab, Structures tab and CANOPUS tab . The output can be imported by dropping the <outputdir> into the SIRIUS GUI application window. Note that the viewer can also export the tree as vector graphics (svg/pdf).

Example 2: MS files

The demo-data/ms/ directory contains two examples of this format. Each file contains a single compound measured with an Orbitrap instrument. To analyze this compound run:

sirius -o <outputdir> -i demo-data/ms/Bicuculline.ms formula -p orbitrap

for formula annotation only or

sirius -o <outputdir> -i demo-data/ms/Bicuculline.ms formula -p orbitrap fingerprint compound-classes structure

to again perform structure database search and compound class annotation.

As the ms file already contains the correct molecular formula, SIRIUS will directly compute the fragmentation tree without decomposing the mass (like when specifying exactly one molecular formula via -f option).

If you want to enforce a molecular formula analysis and ranking (although the correct molecular formula is given within the file) use the --ignore-formula option to ignore molecular the formula in the file. The number of formula candidates can be specified via the -c option.

sirius -o <outputdir> -i demo-data/ms/Bicuculline.ms --ignore-formula formula -p orbitrap -c 5

SIRIUS will now ignore the correct molecular formula in the file and output the 5 best candidates.

Background Service - Generic SIRIUS API

SIRIUS provides a REST API to access data from the project space and to run computations. You can either directly interact with this API or use the Python SDK.

The openAPI specification and documentation can be viewed via the browser. Just start SIRIUS, check which port the service is running on by clicking the “settings” button and open http://localhost:8080/, where 8080 is replaced with your port. SIRIUS may also use a different available port. Please, check the command line output of the starting SIRIUS: SIRIUS Service is running on port: [PORT_NUMBER].

The page should look similar to this:

Foo
SIRIUS API specification.

Since there are so many endpoints, the start may be a bit overwhelming. The following will help you to get an overview and make the best use of the API.

Hello world structure candidates (your first tiny example)

First of all: remember that the API supports multiple SIRIUS projects. That is why you always need to specify the projectId if you want to query a feature.

Say you want to get the structure hits for the feature with name “InterestingCompound12”. You need to do the following. (Note: This can be directly performed via the swagger ui at http://localhost:8080/. Please remember to change the commands matching to your query IDs.)

  • get the list of open project spaces:http://localhost:8080/api/projects

Response:

[
  {
    "projectId": "testdataset",
    "location": "/path/to/testdataset.sirius",
    "description": null,
    "compatible": null,
    "numOfFeatures": null,
    "numOfCompounds": null,
    "numOfBytes": null
  }
]
  • get the list of features: http://localhost:8080/api/projects/testdataset/aligned-features

Response:

[
...
  {
    "alignedFeatureId": "577173392664996156",
    "name": "InterestingCompound11",
    "ionMass": 212.1184774810981,
    "adduct": "[M + ?]+",
    "rtStartSeconds": 478.891,
    "rtEndSeconds": 487.677,
    "computing": false
  },
  {
    "alignedFeatureId": "577173392774048066",
    "name": "InterestingCompound12",
    "ionMass": 461.3699477422347,
    "adduct": "[M + ?]+",
    "rtStartSeconds": 447.536,
    "rtEndSeconds": 456.591,
    "computing": false
  },
...
]
  • search for the feature with name InterestingCompound12 and select its alignedFeatureId.
  • get all structure candiates ranked by csiScore: http://localhost:8080/api/projects/s6tomatoSmall/aligned-features/577173392774048066/db-structures

Response:

[
  {
    "inchiKey": "PPYOSYACEILSKE",
    "smiles": "CCCCCCCCC=CCCCCCCCC(=O)NCCCCC(C(=O)O)N(C)C",
    "structureName": "N2,N2-Dimethyl-N6-[(9Z)-1-oxo-9-octadecen-1-yl]lysine",
    "xlogP": 5.5,
    "csiScore": -198.4107988137411,
    "tanimotoSimilarity": 0.4523809523809524,
    "mcesDistToTopHit": 0,
    "molecularFormula": "C26H50N2O3",
    "adduct": "[M + Na]+",
    "formulaId": "577178082920468525"
  },
  {
    "inchiKey": "URAUKAJXWWFQSU",
    "smiles": "C1CCC(CC1)N(C2CCCCC2)C(=O)COCC(=O)N(C3CCCCC3)C4CCCCC4",
    "structureName": "N,N,N',N'-Tetracyclohexyl-3-oxapentanediamide",
    "xlogP": 6.4,
    "csiScore": -217.50017505980176,
    "tanimotoSimilarity": 0.31736526946107785,
    "mcesDistToTopHit": "Infinity",
    "molecularFormula": "C28H48N2O3",
    "adduct": "[M + H]+",
    "formulaId": "577178082920468526"
  },
...
]

Class hierarchy

The main classes in the hierarchy are projects, alignedFeatures and formulas. These have a one-to-many relation. See below an exemplary representation.

project [projectId:1]
│   ...
│   ...    
│
└───alignedFeature [alignedFeatureId:577173392774048066]
│   │   ms-data
│   │   spectral-library-matches
│   │   db-structures
│   │   denovo-structures
│   │   
│   └───formula [formulaId:577178082920468525]
│   │   │   isotope-pattern
│   │   │   fragtree
│   │   │   fingerprint
│   │   │   lipid-annotation
│   │   │   canopus-prediction
│   │   │   best-compound-classes
│   │   │   db-structures
│   │   │   denovo-structures
│   │   
│   └───formula [formulaId:577178082920468526]
│   │   │   isotope-pattern
│   │   │   ...
│   
└───alignedFeature [alignedFeatureId:577173392664996156]
│   │   ms-data
│   │   ...
│
project [projectId:2]
│   ...
│   ...

Within these classes you can find data and results. Results such as structures are long list and thus also come with a ‘paged’-endpoint (/page). With this hierarchy in mind you can for example

  • select all formula candidates of a feature: /api/projects/{projectId}/aligned-features/{alignedFeatureId}/formulas
  • select all (database) structure candidates of a feature: /api/projects/{projectId}/aligned-features/{alignedFeatureId}/db-structures
  • select all (de novo) structure candidates of a specific molecular formula candidate of a feature: /api/projects/{projectId}/aligned-features/{alignedFeatureId}/formulas/{formulaId}/denovo-structures
  • select the molecular fingerprint of a specific molecular formula candidate of a feature: /api/projects/{projectId}/aligned-features/{alignedFeatureId}/formulas/{formulaId}/fingerprint