2002 Update of Mass Spectral Library released. (General Developments).

A major update to the NIST Mass Spectral Library was released in July. Four years of painstaking work has led to significant enhancements in the coverage and quality of this widely used reference collection. Originating from a number of laboratories, including measurements at NIST for compounds of special importance, over 45 000 high quality reference mass spectra have been added, increasing the number of spectra from 129 138 to 174 948. This has led to an increase in numbers of compounds represented from 108 886 to 147 370, an expansion of more than one-third. Spectra for thousands of compounds have been replaced by higher quality versions, and over 6500 high quality replicate spectra were added. These replacements, along with the policy of adding only complete spectra, have led to an increase in the average number of peaks per spectrum from 96 to 111, and a decline in percentage of spectra having fewer than 10 peaks from 4 % to 0.5 %.

The NIST team of evaluators also has made significant improvements in the representation of the chemical substances in the library. A manual, compound-by-compound examination of chemical names and structures was completed, leading to consistent chemical representation throughout the database. Compounds not fully identified by their chemical structure were removed from the collection, ambiguous representations were eliminated, and thousands of chemical names originating from the laboratory that provided the spectrum were replaced by clearer, more systematic names. In addition, in cooperation with the Chemical Abstracts Service (CAS), all CAS registry numbers were verified by matching against chemical structures, thereby eliminating many inconsistencies and leading to the addition of 35 000 registry numbers. Using a structure-to-name program, tens of thousands of IUPAC-consistent chemical names have been added as synonyms.

Within the next 6 months, we expect that virtually all of the approximately twenty active distributors will provide this update to new and current library customers. Considering the fact that approximately 3 000 new versions of the library are installed on mass spectrometer data systems each year, and at least 30 000 copies of earlier versions have been installed over the years, we anticipate that this effort will have an even more substantial impact.

CONTACT: Stephen Stein, [phone]; stephen. [e-mail].