FOR IMMEDIATE RELEASE:             Roger Rensberger
April 25, 1994                     (301) 975-2762

                                   TN-5974

                    SOFTWARE INNOVATIONS ANNOUNCED FOR

                    NIST/EPA/NIH MASS SPECTRAL DATABASE


     Two important software innovations have been made to the
NIST/EPA/NIH Mass Spectral Database, a major international
resource for analytical chemists and environmental scientists to
use in identifying unknown substances.  The database is available
from the National Institute of Standards and Technology for
scientific instruments and for personal computers.

     The software innovations include a new "Dynamic Link
Library" system that offers distributors of the database a
prepackaged program that can be directly incorporated in mass
spectrometers without any reformatting or indexing.  The PC
version has been updated with new features that provide a more
efficient way of searching the database to reduce the chance that
a correct match will be missed.

     The library of 74,000 electron mass spectra of 62,235
chemical compounds is one of the most widely known standard
reference data products from NIST.  Users include scientists in
the chemical, pharmaceutical, food and beverage, rubber,
petroleum, aerospace, telecommunications and computer industries
as well as hospitals, environmental laboratories and law
enforcement agencies.

     Mass spectrometry is the most extensively used instrument
technique in analytical chemistry.  It involves the ionizing of
molecules of an unknown sample.  These ionized molecules undergo
dissociation (breaking up into simpler parts) and the ionized
fragments then are analyzed according to their mass.  This
generates a "spectrum," which--like a fingerprint--is
characteristic of the chemical species.

     The mass spectral database is distributed by the makers of
mass spectrometers as an integral part of instrument data
systems.  In the past, manufacturers had to reformat and index
the data files from NIST, then write and maintain their own
software for the data collection.  Software developed for the PC
version also is provided for seamless integration in commercial
instruments for the first time.

     The PC version has a new "incremental" name search that
provides a display of dictionary-sorted names that track the
selection entered by the user.  This makes it easy to observe
other similar compound names in the system.  The program allows
the user to search for a particular spectrum by name, chemical
formula or Chemical Abstracts Registry Number; or to search for a
spectrum that matches the spectrum of an unknown chemical
compound.  The PC version also has a file of 12,000 replicate
spectra that were previously available only in commercial
instruments.

     Stephen E. Stein, manager of the NIST Mass Spectral Data
Center, explains that a replicate spectrum is a second or third
spectrum of the same compound, often taken under different
instrument conditions.  Each spectrum is usually similar to
others in its group, but not identical.  Statistical analysis
suggests that a user is more likely to retrieve the correct
spectrum out of a database when replicates are included, said
Stein.

     For information on the 1994 NIST/EPA/NIH Mass Spectral
Database, Standard Reference Database 1, or for 1A, Version 4.5
for PCs, contact the Standard Reference Data Program, 
A320 Physics Building, NIST, Gaithersburg, Md. 20899-0001, 
(301) 975-2208, fax:  (301) 926-0416, e-mail: 
SRDATA@enh.nist.gov (via Internet).

     The PC version is available on 3«-inch high-density disks
for $1,290 (5¬-inch disks available only by special request).  It
requires MS DOS 2.1 or later, 640K memory and a color monitor. 
There also is a CD-ROM version available for $1,200.  It requires
520K memory and a Hewlett-Packard LaserJet or Epson compatible
printer.  Upgrades from all previous PC editions are $200.

     As a non-regulatory agency of the Commerce Department's
Technology Administration, NIST promotes U.S. economic growth by
working with industry to develop and apply technology,
measurements and standards.
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