The absolute amount of d7-LysoGb1 in the vial was determined using quantitative NMR to have the stated value on the vial. The vial may have additional components, but none are isobaric with LysoGb1, d7-LysoGb1, Psychosine, or d5-Psychosine, and these additional components have no effect on the ability to quantify the LysoGb1 or Psychosine.