Unknown Identification, “Known Unknowns,” with Accurate Mass Mass Spectrometry and CAS Registry

This post describes the method we routinely employ to identify unknowns.  We refer to those known in the literature, but unknown to us as “known unknowns.”   The term originated from a speech by Donald Rumsfeld:

http://en.wikipedia.org/wiki/There_are_known_knowns

We published our findings in the Journal of Mass Spectrometry in 2011 and presented the initial results at the ASMS meeting in Salt Lake City, Utah in 2010.

The article was featured on the cover of the Feb 2011 JASMS:

Prepress Version of ASMS Article:

http://www.littledomain.com/james/files/known_unknowns_article.pdf

Poster Session ASMS 2010:

http://www.littledomain.com/james/files/known_unknowns.pdf

New July 2011!  Searching CAS Registry by Formula Weight:  A little known fact that can search SciFinder by formula weight by ”tricking” interface.  Not as good as being able to search by monoisotopic MW, but can be useful occasionally

http://www.littledomain.com/james/files/formula_weight_scifinder.pdf 

Prepress of ChemSpider Article:

http://littlemsandsailing.wordpress.com/2011/05/22/accurate-mass-measurements-identifying-%e2%80%9cknown-unknowns%e2%80%9d-using-chemspider/

Link to Work with NIST and New Exact Mass Software in Version 11:

http://littlemsandsailing.wordpress.com/2011/08/27/using-new-nist-exact-mass-search-to-identify-known-unknowns/