12 urine samples from 6 individuals (2 time points each) enrolled in a study on healthy aging were collected. Samples were frozen at -80⁰C prior to analysis. Samples were thawed, pH neutralized, separated into soluble urine (SU) and urinary pellet (UP) fractions, and subjected to filter aided sample preparation (FASP). FASP-processed samples were subjected to LC-MS/MS analysis on a Q Exactive mass spec.