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NIST and the SWGDRUG Mass Spectral Reference Library of Seized Drugs


The Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG) maintains a database of reference mass spectra, or “molecular fingerprints” of controlled substances. This database is a cornerstone in the fight against illicit drugs, including newly emerging fentanyl analogues and other synthetic opioids. NIST scientists perform rigorous quality assurance on all new mass spectra added to the database, giving confidence to forensic chemists that the results they obtain using this database are accurate and reliable.


Image of a fentanyl mass spectrum shown in a lab notebook
Credit: Arun Moorthy (NIST)

Synthetic drugs such as fentanyl and its analogues are driving an unprecedented epidemic of overdose deaths in the United States. Clandestine labs create these new substances in part to evade law enforcement. This places a major burden on federal, state, and local law enforcement agencies to positively identify compounds that they have never seen before. The SWGDRUG library helps them meet this challenge by providing authoritative, high-quality reference mass spectra for newly emerging illicit compounds.

The SWGDRUG library is distributed freely as a trusted standard for identification of emerging new drugs. In 2020, the SWGDRUG library reached 3400 spectra, making it the largest critically reviewed, publicly available reference library of its kind in the world.

In 2015, SWGDRUG partnered with the NIST Mass Spectrometry Data Center (MSDC) to provide quality assurance. The MSDC ensures data accuracy using a comprehensive method, including thermodynamics, chemical kinetics, and numerical comparisons to reference spectra of structurally similar compounds. The MSDC has been creating mass spectral reference libraries for over 30 years and has unique capabilities and expertise in this area. Quality assurance by NIST’s MSDC helps ensure that identifications using the SWGDRUG are accurate and reliable.

Created February 2, 2021, Updated March 23, 2021