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NIST Standard Reference Database 1A


NIST Mass Spectral Libraries, 2023 Edition with Search Program
Data Version: NIST23
Software Version: 3.0

This database is the product of an ongoing comprehensive evaluation and expansion of the world's most widely used mass spectral reference library.

NIST SRD 1A is available ONLY from distributors.

Contents of the NIST23 Mass Spectral and Retention Index Libraries
Library Description Library File Name Library Contents
NIST/EPA/NIH (EI) Mass Spectral Library 
Main EI MS Library mainlib 394,054 Spectra for 347,100 chemical compounds
Replicate EI MS Library replib 46,954 replicate spectra
Tandem (MS/MS) Mass Spectral Library
HRAM MS/MS Library -
small molecules
hr_msms_nist 1,934,658 spectra of 210,195 precursor ions from 49,590 chemical compounds
Low Resolution MS/MS Library -
small molecules
lr_msms_nist 433,692 spectra of 330,358 precursor ions from 49,865 chemical compounds
APCI High Resolution MS/MS Library -
small molecules
apci_msms_nist 5,714 spectra of 1,121 precursor ions from 561 extractable and leachable compounds
    Total: 2,374,064 spectra of 399,267 precursor ions from 51,501 chemical compounds
GC Method/Retention Index (RI) Library
Retention Index Library


491,790 RI values for 180,610 compounds; 153,472 compounds in the Main Library have retention index data.


  • Tandem (MS/MS) Mass Spectral Library and GC Method/Retention Index (RI) Library may be obtained as separate products.

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.

For more information, please visit:……

The scientific contact for the database is:
Stephen E. Stein
Mass Spectrometry Data Center
National Institute of Standards and Technology
Gaithersburg, MD 20899-8362
(301) 975-2505
massspec [at] (massspec[at]nist[dot]gov)

Keywords: analysis; chemical analysis; chemical databases; chemical structure; chemistry; mass spectra; mass spectrometry.

Created June 19, 2014, Updated November 9, 2023