LIPID MAPS® Computationally-generated Bulk Lipids (COMP_DB)

COMP_DB is a virtual database composed of major classes of lipid species, generated from a list of commonly occurring acyl/alkyl chains. These "Bulk" lipid species indicate the number of carbons and number of double bonds, but not chain positions or double bond regiochemistry and geometry. Note that many of the lipids in COMP_DB may not be relevant to mammalian samples. COMP_DB returns bulk structures that are more useful for users who do not generate MS/MS fragmentation on their platforms. Caution should be exercised when interpreting data from computational databases and great care in their reporting exercised. A common problem when trying to identify large numbers of lipids is that a single m/z value can represent many isobaric/isomeric species. Thus, when using high resolution MS with no fragmentation, it is essential to conduct only Bulk searches so that the correct level of shorthand notation is returned to the user. COMP_DB is provided to help address this, and is aligned to the new shorthand update published here. Note that if you are using mammalian tissue, you may prefer to do a Bulk search with LMSD instead to restrict to more relevant lipids.