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NIST20: 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 2017 version. The new versions, NIST20, are available from distributors for integration with existing instrumentation.


NIST Tandem Mass Spectral Library, 2020 release

  • 31,000 compounds
  • Twice as many as the 2017 release
  • 186,000 precursor Ions 
  • 1.3 million spectra


Fragmentation methods

  • 27,840 HRAM (high res accurate mass) compounds
  • 29,890 QTOF, HCD, IT-HRAM, QqQ compounds
  • 29,444 ion trap compounds (low res., up to MS4)
  • 246 APCI HRAM “extractables and leachables”

Precursor ion types

  • 26,575 protonated
  • 12,589 deprotonated
  • 10,032 water/ammonia loss
  • 34,199 other in-source generated

Wide variety of compounds

Spectra of Vitamin D3 metabolite
Vitamin D3 metabolite
Spectra of fentanyl drug
Fentanyl drug
Spectra of malathion insecticide
Malathion insecticide
  • Marbofloxacin antibiotic
  • 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 types of compounds and spectra in library

75% (+), 25% (-)

32% MS2 of in-source

8% of MSn

6,000 human metabolites

Screenshot of MS Interpreter




MS Interpreter

Connect peaks to structures

Hybrid Search

Identify compounds not in the library

Screenshot of Hybrid Search
Screenshot of hybrid search

NIST/EPA/NIH EI-MS Library, 2020 release

350,704 electron ionization (EI) spectra

  • 306,643 compounds, 43,774 replicate spectra
  • 39,729 more compounds than NIST 17

447,289 retention index (RI) values

  • 139,382 RI compounds – 40 K increase
  • 114,629 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

MS Interpreter

Connect peaks to structures

Screenshot of MS Interpreter


New compound selection process

schematic of compound selection process

New evaluation process

schematic of evaluation process

New library building method

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


Created June 11, 2020, Updated June 12, 2020