Clinical Mass Spectrometry Core

Peter J. Walter, Ph.D., Director

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The mission of the NIDDK’s Clinical Mass Spectrometry Core (CMSC) is to collaborate with investigators from NIDDK and other institutes within NIH on quantitative mass spectrometry analyses. This includes the analysis of doubly labeled water, stable isotope tracer studies, drugs and drug metabolites, and small molecules by liquid chromatography–mass spectrometry (LC-MS) and isotope ratio mass spectrometry (IRMS).

The CMSC supports all stable isotope applications in NIDDK’s clinical labs and to advise, develop, and validate novel stable isotope-labeled research assays in collaboration with ongoing clinical research projects. Our primary emphasis was on the clinical measurement of total energy expenditure (TEE) by doubly labeled water (DLW). TEE is the total energy a person or animal uses in a day for activities, including rest. TEE is an important measurement used in determining dietary and exercise needs. Additionally, stable isotope enrichment tracers including 6,6-D2-glucose, D5-glycerol, and U-13C-palmitate, are used to assess metabolic parameters.

Using LC-MS the CMSC quantitatively measurement of drugs, drug metabolites and other small molecules by high resolution-accurate mass LC-MS and triple quadrupole LC-MS. Methods include but not limited to:

• Free Fatty Acids, Total Fatty Acids, Long-chained Fatty Acids, Short-chained Fatty Acids, Non-Nutritive Sweeteners - Sucralose, Acesulfame-K, Saccharin, Stevia, Bile Acids, Metformin, Mirabegron, Nitrite-nitrate.
• To maintain analyses the CMSC uses minimal cost recovery for NIDDK projects and cost recovery for non-NIDDK projects.