Spectral library searching is currently the most common approach for compound annotation in untargeted metabolomics.  We describe existing spectral library resources, highlight different strategies for compiling spectral libraries, and discuss quality considerations that should be taken into account when interpreting spectral library searching results. 
Spectral library searching
This review focuses on the current state of spectral libraries for untargeted LC-MS/MS based metabolomics. 
LC-MS/MS
Finally, we describe how spectral libraries are empowering the next generation of machine learning tools in computational metabolomics, and discuss several opportunities for using increasingly accessible large spectral libraries.



machine learning tools