==== NIST 23 Tandem Mass Spectral Libraries ====
{{ :chemdata:asms2023:asms2023_nist23_features.pdf |NIST 23 Release Flyer}}
* **51,501 compounds** 60% increase over NIST 20!
* **2,374,064 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
* **399,267 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 | 49,145| 157,330| 1,735,530|
^ ::: |Ion Trap | 46,471| 186,392| 199,128|
^ Small Molecule Low \\ Resolution MS/MS \\ Library (lr_msms_nist) |Beam Type \\ Collision Cell | 3,346| 5,751| 64,137|
^ ::: |Ion Trap | 49,113| 328,503| 369,555|
^ Small Molecule APCI2 \\ High Resolution MS/MS \\ Library (apci_msms_nist) |Beam Type \\ Collision Cell | 561| 1,121| 5,714|
^ \\ All |Beam Type \\ Collision Cell | 50,285| 160,473| 1,805,381|
^ ::: |Ion Trap | 49,561| 380,654| 568,683|
^ Total | | 51,501| 399,267| 2,374,064|
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 (58% of the spectra) ^
^• MSn (12% of the spectra) ^
{{:chemdata:asms2023:left1_nist_23_num_compounds.png?direct&340|}}{{:chemdata:asms2023:right1_nist_23_num_spectra.png?direct&340|}}
{{:chemdata:asms2023:left2_nist_23_public_db.png?direct&340|}}{{:chemdata:asms2023:right2_nist_23_pie_chart.png?direct&340|}}
The NIST Tandem MS Library and Search Program is available from these **[[:chemdata:distributors|distributors]]**
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