Isotope Ratio Measurements

The Mayo Clinic Metabolomics Core offers stable isotope-labeled tracer methodologies to investigators across various disciplines. Targeted metabolomics with tracers provide greater insights into the dynamics and fluxes of metabolic pathways and promise robust statistical models for distinguishing sample classes with better classification accuracy.

The core supports the measurement of protein, glucose, fat metabolism and gastric-emptying studies using a variety of mass spectrometric techniques. The core has established methods for measuring the isotopic enrichment of the following analytes:

Amino acids

[ring-13C6]phenylalanine [2H5]phenylalanine [1-13C;15N]leucine [ring-13C6]tyrosine
2H4]tyrosine [13C]ketoisocaproic acid [15N]tyrosine [1-13C]leucine
[15N]glutamate [15N]glutamine [15N]ornithine [15N]aspartate
[15N]arginine [15N]citrulline [15N]proline [15N]glycine
[15N]lysine [15N]aminoadipic acid [13C]aminoadipic acid


[6,6-2H2]glucose [1-13C]glucose [U-13C]glucose


[1-13C]octanoate [U-13C]palmitate [13C4]palmitate [2H9]palmitate
[U-13C]linoleate [U-13C]oleate [2H5]glycerol [U-13C]linoleoylcarnitine
[U-13C]palmitoylcarnitine [13C4] palmitoylcarnitine [U-13C] oleoylcarnitine [U-13C]18C16-ceramide


[2H4] cortisol [2H3] cortisol [4-13C] cortisol [2H3] cortisone
[2H7] cortisone

Tricarboxylic acids

[13C]lactate [13C]alanine [13C]fumarate [13C]succinate
[13C]alpha-ketoglutarate [13C]malate [13C]citrate [13C]isocitrate
[13C]glutamine [13C]glutamate

Isotopologues analysis

  • Incorporation of 13C6-glucose or 13C6-glutamine into TCA analytes
  • Incorporation of 13C6-glucose into NEFA and sphingolipids analytes