NIST26 Tandem Mass Spectral Libraries


NIST26 Release Flyer

This webpage highlights the key features of the NIST26 Tandem Mass Spectral Libraries. These libraries provide high-quality, comprehensive spectra of analytically important compounds and are widely used for compound identification in metabolomics, food science, health, agriculture, environmental research, pharmaceuticals, forensic studies, etc.

  • 68,635 compounds 33% increase over NIST23!
  • 3,219,115 tandem spectra with a wide range of fragmentation conditions including positive and negative modes from ion-trap (up to MS4) and ‘beam-type’ collision cells (QTOF, HCD, and QqQ); new spectra acquired at high accuracy and resolution
  • 567,114 precursor ions including in-source fragments


Library Instrument Type Compounds Precursor
Ions 		Spectra
Small Molecule HRAM1
MS/MS Library
(hr_msms_nist) 		Beam Type
Collision Cell 		66,282 211,814 2,347,204
Ion Trap 63,198 268,484 291,845
Small Molecule Low
Resolution MS/MS
Library (lr_msms_nist) 		Beam Type
Collision Cell 		3,346 5,750 64,111
Ion Trap 65,857 455,057 509,562
Small Molecule APCI2
High Resolution MS/MS
Library (apci_msms_nist) 		Beam Type
Collision Cell 		623 1,339 6,403

All 		Beam Type
Collision Cell 		67,382 215,029 2,417,718
Ion Trap 66,430 542,389 801,397
Total 68,635 567,114 3,219,115

1 - HRAM: High Resolution Accurate Mass.
2 - APCI: Atmospheric Pressure Chemical Ionization; for extractable and leachable compounds.

Most Common Precursor Ions

Positive Precursors:

[M+H]+, [M+H-H2O]+, [M+Na]+, [M+2H]2+, [2M+H]+, [M+H-2H2O]+, [M+H-NH3]+, [M+NH4]+, [M-H+2Na]+, [M+K]+, [M+H+K]2+, [M+H+Na]2+, [M+2Na]2+, [M-2H+3Na]+, and others

Negative Precursors:

[M-H]-, [M-2H]2-, [M-H-H2O]-, [M+Cl]-, [M-H-CO2]-, [M+HCO2]-, [2M-H]-, and others

• 77% positive mode, 23% negative mode
• In-source Fragments (50% of the spectra)
• MSn (13% of the spectra)

The NIST Tandem MS Library and Search Program is available from these distributors