XCMS-MRM and METLIN-MRM: a cloud library and public resource for targeted analysis of small molecules

We report XCMS-MRM and METLIN-MRM ( http://xcmsonline-mrm.scripps.edu/ and http://metlin.scripps.edu/ ), a cloud-based data-analysis platform and a public multiple-reaction monitoring (MRM) transition repository for small-molecule quantitative tandem mass spectrometry. This platform provides MRM transitions for more than 15,500 molecules and facilitates data sharing across different instruments and laboratories. A resource of multiple reaction monitoring–mass spectrometry transitions for quantitative analysis of biological small molecules is provided in METLIN-MRM, along with automated tools for analyzing such data in XCMS-MRM.