This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Pooled human serum samples from a large population will be studied to determine their metabolome. Premade standards will also be examined and the FMQ method will be used to give absolute concentrations of individual compounds in the sample. The goal is to find the true concentrations of as many metabolites as possible in the serum of the average human.