The NIST Mass Spectral Library is the world's most widely used and trusted resource for identifying mass spectra. The NIST 26 EI Library has 431K spectra for 382,180 compounds and over 527K literature and experimentally determined GC Methods and Retention Indexes for 216K compounds. NIST now records the RI values of all measured spectra, including the GC/MS Method with the spectrum when it is added to the user library. NIST 26 includes the standalone Mass Spectral Search Program, v.4.0, and the powerful AMDIS mass spectral deconvolution software.
The MS Search 4.0 program also introduces a powerful new "Chromatogram" tab that integrates AMDIS deconvolution functionality and can open multiple data file formats containing either low or high-resolution spectra.
In addition, the NIST 26 Tandem (MS/MS) Mass Spectral Library includes 68,635 compounds and 3.2 million spectra. The standalone version of the Tandem Library includes Lib2NIST and the MoNA MSMS Library of 154K spectra in the NIST MS Search Format ready for use with the Hybrid Search. This is an exclusive from Diablo Analytical.
The Mass Spectral Search Program, v.4.0, interfaces to several different mass spectrometer manufacturer's data analysis software and is compatible with third party mass spectral libraries such as Designer Drugs 2018 and the Robert Adams Flavor and Fragrance libraries.
Exclusive from Diablo, each purchase of the NIST 26 EI Mass Spectral Library also includes a copy of the standalone NIST GC Method/Search Package that includes the ability to search a Retention Index range. This capability is not available in the standard NIST MS Search Program. This optional item is provided for FREE; making the Diablo NIST offering the most cost effective for GC/MS.
Important News
NIST 26 Mass Spectral Libraries Now Shipping!
The National Institute of Standards and Technology (NIST) has announced the June 1st, 2026 release of the NIST 26 version of the Mass Spectral Libraries. The libraries (EI, MS/MS) are now sold and distributed as separate standalone individual libraries. The Retention Index (RI) library is included with the EI library, but is also sold as a separate standalone library.
EI/RI Library Details: NIST26-flyers EI
Tandem (MS/MS) Library Details: NIST26-flyers Tandem
NIST Mass Spectrometry Data Center Site: https://chemdata.nist.gov/dokuwiki/doku.php?id=start
Purchase NIST 26 New and Upgrade Licenses
Important: The NIST 26 version of MS Search (version 4.0) is only compatible with 64-bit versions of the Microsoft Windows operating systems. Please contact Diablo Analytical if you want to use one of the NIST 26 libraries on a 32-bit version of Microsoft Windows.
NIST 26 Demo Libraries
NIST has released new "demo" libraries that can be downloaded for free. The demo libraries include the MS Search 4.0 program and small demostration libraries.
EI Demo Library: https://chemdata.nist.gov/dokuwiki/doku.php?id=ei_search_program_demo
MS/MS Demo Library: https://chemdata.nist.gov/dokuwiki/doku.php?id=tandem_search_program_demo
NIST 23 Availability
We will also continue to sell the NIST 23 Libraries at current prices through the end of September, 2026.
Important Information About NIST 26:
- The NIST 23 and NIST 26 Mass Spectral Libraries (EI and Tandem) can not be converted to SDF or MSP text file formats using the Lib2NIST program. The ability to do this with previous versions of the NIST Library was accidental, and has been disabled in NIST 23 and NIST 26.
Overview
NIST 26 includes the following:
- Main EI MS Library: 431K Spectra for 382,180 chemical compounds (35K more than NIST 23).
- Tandem (MS/MS) Library: 68,635 compounds (33% more than NIST 23).
- Tandem (MS/MS) Library: 3.2 million spectra.
Exclusive: Diablo’s version of the NIST 26 Tandem Library includes Lib2NIST and the MassBank of North America (MoNA) LC/MSMS library of 153,633 spectra in the NIST Tandem format indexed for the NIST Hybrid Search; all for no additional charge.
- GC Method/Retention Index Library: This library includes 527K RI values and GC Methods for 216K compounds - > 35K increase. Also Includes the NIST RI Search Program, which is optimized for retention-index searches.
The NIST Method/RI Search Program is included for FREE with the purchase of either the NIST 26 EI Mass Spectral Library or the Standalone RI library.
- NIST MS-Search 4.0: The standalone NIST Mass Spectral Search Program. Includes a powerful new "Chromatogram" tab that integrates AMDIS deconvolution functionality and can open multiple data file formats containing either low or high-resolution spectra.
- AMDIS: The Automated Mass Spectral Identification and Deconvolution System.
- Mass Spec Interpreter: A tool that allows an associated structure and spectrum to be evaluated with respect to fragmentation. Can me used with molecular or adduct ions (like MH+) with integer or accurate mass.
Evaluation and Quality Control
- Each spectrum critically examined by experienced mass spectrometrists.
- Each chemical structure examined for correctness and consistency, using both human and computer methods.
- Spectra of all stereoisomers intercompared.
- Chemical names examined by experts and IUPAC names provided.
- Thousands of spectra replaced with higher quality measurements.
- Verified CAS registry numbers.
Available Configurations of the NIST Mass Spectral Library
The NIST 26 Mass Spectral Library is available in the following configurations:
- NIST 26 EI Library for Mass Spectrometry (mainlib and replib), also includes the GC Methods/Retention Time Library. Optional macros are available for seamless integration of the NIST Library with Agilent ChemStation and MassHunter. Can optionally be purchased with the EI Library in the Agilent ChemStation/MassHunter ".L" format.
- Upgrade Version of the NIST 26 EI Library for Mass Spectrometry, available at a reduced price to anyone who provides evidence of prior ownership of NBS 98, NIST 02, NIST 05, NIST 08, NIST 11, NIST 14, NIST 17, NIST 20, or NIST 23. As in the case of the full license, optional macros are available for seamless integration of the NIST Library with Agilent ChemStation and MassHunter. Can optionally be purchased with the EI Library in the Agilent ChemStation/MassHunter ".L" format.
- NIST 26 Standalone Tandem (MS/MS) Library, is comprised of two databases. One has spectra for compounds over a wide range of collision energies, ranging from slight to complete dissociation of the precursor ion. The other has spectra of commercial peptides. Recently the NIST MS/MS library has been added to Thermo’s data system software for all tandem mass spectrometers.
- NIST 26 Standalone GC Methods/Retention Index Library with expanded constraints to help narrow retention time search. With the results from the NIST Mass Spectral Library and the Retention Index Database, you can identify and confirm compound identity in one step.
- NIST 26 Bundles that include the NIST 26 EI/RI and Tandem (MS/MS) Libraries at a discounted price relative to purchasing individual standalone licenses. The bundles include individual licenses for the EI/RI and MS/MS libraries, allowing you to install them on the same or different computers.
Get the Most Out of Your NIST Mass Spectral Library
Have you wondered whether you are getting the best results from your NIST searches? Are there other ways to confirm the identity of your unknown compound? Wouldn’t it be nice to be able to read a spectrum? What is this hybrid search, anyway?
The answers to these questions and more are available through Mass-SpecTraining.com. Available either in a classroom setting, or Live-on-the-web, or self-paced, there is a format that will fit your location, schedule, and learning goals.
The Mass Spectral Interpretation Course is conducted by O. David Sparkman who is currently an Adjunct Professor of Chemistry at the University of the Pacific in Stockton, California; Contractor to the National Institute of Standards and Technology Mass Spectrometry Data Center; President of ChemUserWorld.com; and a former American Chemical Society Instructor (1978–2006) and American Society for Mass Spectrometry Member-at-large for Education (2004–2006).
MS Master Class Webinar Series: Effective Use of Mass Spectral Databases
FREE Training for NIST 26 EI and MSMS libraries and software by James Little, a retired Research Fellow from Eastman Chemical Co. where he identified unknowns by LC-MS and GC-MS for >40 years..
- YouTube Videos
- Associated Handouts
- Test Files
- Resources
- Free LIbraries
Additional Resources
Links:
- NIST Mass Spectrometry Data Center: http://chemdata.nist.gov/
Publications:
Free Downloads:
- Mass Spectrum Interpreter: This is a utility developed and used in the NIST Mass Spectrometry Data Center to assist in the evaluation of mass spectra. It finds possible structural origins of peaks in a mass spectrum and provides formula and isotopic processing utilities. It can operate in conjunction with the NIST MS Search Program or standalone.
- NIST 26 EI Demo Library
- NIST 26 MS/MS Demo Library
Other Mass Spectral Libraries
- Essential Oil Components by GCMS – Version 4 by Robert Adams Important: The NIST 23 and NIST 26 EI Library and Wiley Registry now include the spectra from Version 4 of the Adam's Library.
- MassBank of North America (MoNA) LC/MSMS Library of 153,633 spectra. Exclusive: Diablo’s version of the NIST 26 Tandem Library includes Lib2NIST and the MassBank of North America (MoNA) LC/MSMS library of 153,633 spectra in the NIST Tandem format indexed for the NIST Hybrid Search; all for no additional charge.
- NIST Polymer Pyrolysis Search Software and Library The NIST Polymer Pyrolysis Search software and library is an R Shiny search app and associated library. This app is for the identification of polymers by pyrolysis breakdown products.
Software Licensing
Use of any NIST Mass Spectral Database is limited to a single computer by a single user at any one time. There is no restriction as to multiple copies in the same or multiple formats on the same single user computer or to backup copies which are for management purposes and not for use on any other computer. In the event of an upgrade from a previous version of any Database, that previous version of the Database may not be installed on another computer and used in the same time period as the upgrade. The previous version may continue to be used on the same single-user computer on which the upgrade is installed.
Purchase
Diablo Analytical is an authorized distributor of the NIST Mass Spectral Library.
Note: The NIST 26 distributions range from 180 MB to 6.9 GB in size. So a fast, reliable Internet connection is recommended for downloading the distribution Zip files.
| Distribution | Distribution Size |
| NIST 26 EI/RI Library | 1.2 GB |
| NIST 26 EI/RI Library plus Agilent Format EI Library | 1.6 GB |
| NIST 26 Tandem (MS/MS) Library plus MoNA LC-MS-MS Library | 6.1 GB |
| NIST 26 RI Library | 180 MB |
| NIST 26 Bundle (EI/RI + MS/MS) | 6.5 GB |
| NIST 26 Bundle (EI/RI + MS/MS) plus Agilent Format EI Library | 6.9 GB |
Upgrades: You can upgrade from an earlier version of the NIST Full or EI Library to the NIST 26 EI Library for a discounted price.
Important: in order to receive the upgrade pricing, NIST requires documentation of ownership of a previous version of the NIST Full or EI Mass Spectral library. You will need to provide this documentation before we will ship an upgrade order or provide a download link. This documentation can take the form of any of the following:
- The original purchase documentation.
- A photo of the original DVD.
- A screen capture of the “About” screen of the NIST MS Search program.
- A screen-capture showing the folder contents of your current version of the NIST Mass Spectral Library.
NIST 26 Mass Spectral Libraries
Software Requirements
NIST 26 and MS Search 4.0 are NOT compatible with Windows 3.x, 95, 98, Me, NT 3.x, Windows NT 4.0, Windows 2000, and Windows XP before SP3, or any 32-bit Windows operating system*.
NIST 26 and MS Search 4.0 are fully compatible with the 64-bit versions of XP, Vista, Windows 7, Windows 8, Windows 10, and Windows 11*.
* Please contact Diablo Analytical if you want to use the NIST 26 libraries with a compatible version of MS Search on a 32-bit version of Windows.
Software Options
The NIST 26 libraries are now sold and distributed as separate standalone individual libraries: EI, and Tandem (MS/MS). The Retention Index (RI) library is included with the EI library, but is also sold as a separate standalone library.
Exclusive: Diablo’s version of the NIST 26 Tandem Library includes Lib2NIST and a download link for the MassBank of North America (MoNA) LC/MSMS library of 153,633 spectra in the NIST Tandem format indexed for the NIST Hybrid Search; all for no additional charge.
NIST 26 Bundles are also available that include the NIST 26 EI/RI and Tandem (MS/MS) Libraries at a discounted price relative to purchasing individual standalone licenses. The bundles include individual licenses for the EI/RI and MS/MS libraries, allowing you to install them on the same or different computers.
You can also purchase the NIST 23 EI library and Bundle with additional EI data in the Agilent Technologies ".L" format for MSD ChemStation and MassHunter.
NIST 26 New Licenses
NIST 26 Bundles
NIST 26 Upgrades
Important: Proof of ownership of a previous version of the Full or EI NIST Mass Spectral Library is required for NIST 26 EI Library Upgrades.
NIST 23 Full Mass Spectral Library
IMPORTANT: The NIST 23 Libraries can continue to be purchased through the end of September, 2026, after which only the NIST 26 libraries can be purchased.
The Full NIST 23 Library includes NIST/EPA/NIH EI and Tandem Libraries, GC Method/RI Database, and Associated Software including the NIST GC Method/RI Database Search Program at NO ADDTIONAL Charge. You can also purchase the Full NIST 23 library with additional EI data in the Agilent Technologies ".L" format for MSD ChemStation and MassHunter.
NIST 23 Standalone Mass Spectral Libraries
If you don't need all of the features included in the Full NIST 23 Library, you can also purchase the following standalone libraries. However, please note that these libraries are also included in the Full NIST 23 Library.
Exclusive: Diablo’s version of the NIST 23 Tandem Library includes Lib2NIST and a download link for the MassBank of North America (MoNA) LC/MSMS library of 143,000 spectra in the NIST Tandem format indexed for the NIST Hybrid Search; all for no additional charge.