NIST26: the mass spectral library grows to 382,180 compounds in the EI part and 68,635 in the tandem part
On 9 June 2026 NIST announced a new release of its mass spectral library (Standard Reference Database 1A), used since 1988 to identify unknown substances in food, drugs, cosmetics, the environment and forensic evidence. About 35,000 compounds were added to the electron ionisation part and 17,000 to the tandem part.
- The EI library (NIST/EPA/NIH, 2026 release) covers 382,180 compounds, 431,000 electron ionisation spectra and 527,000 retention index values; 216,000 compounds have both an EI spectrum and a retention index, and AI-based retention index estimates are given for all compounds.
- The tandem (MS/MS) library contains 68,635 compounds — 33 % more than the 2023 release — with 567,000 precursor ions and 3.2 million spectra; 66,782 compounds have high-resolution accurate-mass (HRAM) spectra.
- New compounds include minor cannabinoids, nitazenes (potent opioids), thiophenes, alkylated polycyclic aromatic hydrocarbons and an expanded set of PFAS — from the US EPA PFAS list, 275 compounds were added to the EI part (961 in total) and 116 to the tandem part (296 in total).
- The library comes preinstalled on many commercial mass spectrometers; the update is bought from the instrument manufacturer or an independent distributor. Before release NIST evaluates the spectra in a software-based review process.