Tech Tip 30: Analysis of Unknowns - How? - Libraries! Part III: GC-MS

In GC-MS, library integrity has massively evolved compared to 25 years ago. In those times the NBS library had 72000 compounds, this was superseded by a Wiley library of 230000 compounds in the late 90's that for the first time contained multiple synonyms, greatly helping identifications. NIST libraries became mainstream around the year 2002 and are re-issued every three years.

In GC-MS we are spoiled in that the analytical conditions are fairly simple and everyone around the world generates their spectra using 70 eV electron ionisation, thereby giving uber-robust and therefore repeatable reference data.


Courtesy of NIST

Courtesy of NIST

The search functions are powerful and varied, synonyms are plentiful and Retention Index data is widely included.