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NIST23: Updates to the NIST Tandem and Electron Ionization Spectral Libraries


The latest release of the NIST Mass Spectral Library, which includes the NIST Tandem Mass Spectral Library and NIST/EPA/NIH Mass Spectral Library and NIST GC Retention Index Database greatly increases the number of compounds and spectra since the 2020 version. The new versions, NIST23, are available from distributors for integration with existing instrumentation.


NIST Tandem Mass Spectral Library, 2023 release

  • 51,501compounds
  • 60% increase over the 2020 release
  • 399,267 precursor Ions 
  • 2.4 million spectra


Fragmentation methods

  • 49,590 HRAM (high res accurate mass) compounds
  • 51,292 QTOF, HCD, IT-HRAM, QqQ compounds
  • 49,561 ion trap compounds (low res., up to MS4)
  • 561 APCI HRAM “extractables and leachables”

Precursor ion types

  • 44,191 protonated
  • 19,620 deprotonated
  • 14,318 water/ammonia loss
  • 44,547 other in-source generated

Wide variety of compounds

Mass spectrum of Perfluorodecanoic Acid (PFAS)
Perfluorodecanoic Acid - PFAS
Mass spectrum of Strictamine, an Alkaloid
Strictamine - Alkaloid
Mass spectrum of Neocurdione, a plant volatile
Neocurdione - Plant Volatile
Spectra of Vitamin D3 metabolite
Vitamin D3 metabolite
Spectra of fentanyl drug
Fentanyl drug
Spectra of malathion insecticide
Malathion insecticide
  • Tribenoside - vasoprotective drug
  • Naphthalene E&L, APCI
  • Luteolin glucoside flavone
  • Retinoic acid metabolite
  • Fuc-GM1(d18:1/16:0) glycolipid
  • and more

Types of compounds and spectra

Pie chart of the types of compounds and spectra found in NIST23 including in order of abundance, environmental related, plant metabolites, human metabolites, food, drug, biopeptides and others)
Pie chart of types of compounds and spectra found in NIST23






MS Interpreter

Connect peaks to structures

Screenshot of MS Interpreter
Screenshot of MS Interpreter

Hybrid Search

Identify compounds not in the library

Screenshot of Hybrid Search
Screenshot of hybrid search

NIST/EPA/NIH EI-MS Library, 2023 release

394,054 electron ionization (EI) spectra

  • 347,100 compounds, 46,954 replicate spectra
  • 40,231 more compounds than NIST 20

491,790 retention index (RI) values

  • 180,610 RI compounds – 40 K increase
  • 153,472 compounds with both RI & MS

Thousands of new compounds of analytical interest

Measured at NIST, thoroughly evaluated

Spectra of loliolide plant metabolite
Loliolide plant metabolite
Spectra of pretomanid antibiotic
Pretomanid antibiotic
Spectra of gardenia amide flavor/fragrance
Gardenia amide flavor/fragrance
  • Human and plant metabolites
  • Flavor/fragrance – food
  • Drugs and their metabolites
  • Forensics, toxins
  • Pesticides – contaminants
  • Industrial chemicals
  • Petrochemicals
  • Surfactants, lipids … and more


NISTMS.exe user interface

Screenshot of hybrid search function



New compound selection process

schematic of compound selection process

New evaluation process

Schematic of the NIST23 process used to evaluate spectra included in the library

New library building method

  • Select compounds, measure spectra
  • Organize by structure
  • Multiple Evaluations
  • MS Interpreter
  • Hybrid Search


Created June 11, 2020, Updated August 11, 2023