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 stable isotope tracer studies, doubly labeled water, drugs and drug metabolites, and small molecules by liquid chromatography–mass spectrometry (LC-MS), gas chromatography–mass spectrometry (GC-MS) and isotope ratio mass spectrometry (IRMS).

The CMSC was initially established to support 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 calculation used in determining dietary and exercise needs. It has been used extensively in obesity research.

Currently, one of the main emphasis of the CMSC is the measurement of metabolic parameters using stable isotope tracers and non-labeled metabolic tracers. These include but are not limited to 6,6-D2-Glucose, D5-glycerol, and U-13C-palmitate.

Key to the CMSC is also the quantitative measurement of drugs, drug metabolites and other small molecules by high resolution-accurate mass LC-MS and by triple quadrupole LC-MS. Alternatively, and for the same purposes, the CMSC performs quantitative analysis by GC-MS.