NIST/EPA/NIH mass spectral database

S.R. Heller, The history of the NIST/EPA/NIH mass spectral database, Today s Chemist at Work, 8(2) (1999) 45-50. 

Provided El spectra have been measured under some sort of standard conditions (70 eV, ion source at 150-250 °C, pressure in the order of 10 " Pa), they exhibit very good reproducibility. This is not only the case for repeated measurements on the same instrument, but also between mass spectrometers having different types of mass analyzers, and/or coming from different manufacturers. This property soon led to the collection of large El mass spectral libraries, either printed [76-78] or computerized. [79] The best established El mass spectral databases are the NIST/EPA/NIH Mass Spectral Database and the Wiley/NBS Mass Spectral Database, each of them giving access to about 120,000 evaluated spectra. [80-83]... 

Spectral data for Exercise 22-F from NIST/EPA/NIH Mass Spectral Database.8... 

The NIST/EPA/NIH Mass Spectral Database (SRData enh.nist.gov) includes more than 100 000 compounds. The Wiley/NIST Registry of MS data is available from Palisade Corp. at http //www.palisade-ms.com. Electron ionization mass spectra of many compounds can be viewed at http //webbook.nist.gov/chemistry. 

Three main spectra collections now exist. The first is the NIST/EPA/NIH mass spectral database, which contains 190 000 spectra of 163 000 compounds [1]. This original collection of spectra and related information is produced by the National Institute of Standards and Technology (NIST) with the assistance of expert advisors from the Environmental Protection Agency (EPA) and National Institutes of Health (NIH). This library is available on CD-ROM for personal computers with integrated tools for GC/MS deconvolution, mass spectra interpretation and chemical substructure identification. This US government publication is very cheap and of very high quality. This library is widely spread in many commercial mass spectrometers. Mass spectra for over 15 000 compounds are accessible on-line [2],... 

The 2008 version of the NIST/EPA/NIH Mass Spectral Database [77,83] contains about 222,000 El spectra of more than 192,000 compounds plus roughly 28,000 replicate spectra. For almost 43,000 compounds there is a conpilation of 293,000 Kovats retention index (KRI) values as determined on nonpolar and polar columns. Since 2005, this database also offers CID spectra, which actually sum up to 14,800 spectra of about 5,300 different ions. The reason for the larger number of spectra over the number of ions is the inclusion of multiple spectra for a given ionic species as obtained by nozzle-skimmer dissociatio and CID on triplequadru-pole or quadrupole ion trap instruments, respectively [84]. The NIST/EPA/NIH Mass Spectral Database is available as a stand-alone version or with - most probably - any commercial mass spectrometer that can be equipped with an El ion source. 

Example The NIST/EPA/NIH mass spectral database (V 2.0, 2005) was searched for spectra corresponding to the molecular formula CgHioClN. Eleven compounds were found, two of which were present with replicate spectra from different sources. Figure 5.17 shows the screenshot where the second spectrum... 

Compounds were identified by first comparing their mass spectra with those contained in the NIST/EPA/NIH Mass Spectral Database or in previously published literature. Wherever possible, identities were confirmed by comparison of LRI values, with either those of authentic standards or published values. Quantities of the volatile compounds were approximated by comparison of their peak areas with that of the 1,2-dichlorobenzene internal standard, obtained from the total ion chromatograms, using a response factor of 1. A Student t-test was carried out on the quantitative data for each compound identified in the GCMS analyses. 

MS + LRI, mass spectrum and LRI agree with those of authentic compound ms + Iri, mass spectrum identified using NIST/EPA/NIH Mass Spectral Database and LRI agrees with literature value (23) ms, mass spectrum agrees with spectrum in NIST/EPA/NIH Mass Spectral Database or with other literature spectrum. 

Spectral data banks There are several which offer real spectra of several tens of thousands of compormds in infrared, proton and carbon-13 NMR, and mass spectrometry. For example The Aldridi/ACD Library of FT-NMR Spectra (12 000 spectra) Nicolet/Aldridi FT-IR Condensed Phase Library (18500 spectra) NIST/EPA/NIH Mass Spectral Database (130000 spectra). 

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