Core Director

John Turk, MD, PhD
Campus Box 8127
314-362-8190
314-362-8188 (fax)

Core lab contacts:
Dr Turk (see above)

Lab Location:
8th fl Southwest Tower

 

Mass Spectrometry Core

The Mass Spectrometry (MS) Core provides MS analyses to DRTC Investigators in order to quantitate and/or to determine structures of diabetes-related biomolecules. The Core increases efficiency and cost effectiveness by providing centralized, standardized analyses to study molecular mechanisms of the pathogenesis of diabetes, its risk factors, and its complications. Specific objectives are:

  • To train students/fellows in principles of MS and use of MS systems, e.g., gas chromatography (GC)/MS, isotope ratio (IR)/MS, electrospray ionization (ESI)/tandem MS (MS/MS), and matrix assisted laser desorption ionization (MALDI)/time of flight (TOF)/MS;
  • To develop new MS methods to identify and quantitate biomolecules;
  • To perform service MS analyses, e.g. quantitation of target analytes and obtaining spectra for structural identification;
  • To assist DRTC Investigators in developing MS assays;
  • To consult in interpreting MS data;
  • To provide and maintain functional MS systems for use in diabetes research;
  • To perform collaborative diabetes research involving Core staff;
  • To reduce diabetes research costs by providing centralized MS services at a fraction of the cost of commercial MS services or of maintaining instruments in individual investigators’ laboratories.

Detailed List of Services

  • Electrospray ionization (ESI) mass spectrometric (MS) and tandem MS (MS/MS) analyses of complex lipids, including phospholipids, polyphosphoinositides, phosphatidylalcohols, lysophospholipids, neutral acylglycerols, sphingolipids, glycosphingolipids, acyl-carnitines, and related molecules for qualitative structural identification or for quantitation in conjunction with internal standards.
  • Collaborative assistance and instruction in extraction, purification, and, when needed, derivatization of complex lipid species from biological materials in preparation for ESI/MS analyses.
  • Gas chromatographic (GC) mass spectrometric (MS) analyses of arachidonic acid, its metabolites, and other fatty acids and their metabolites in electron impact (EI), positive ion methane chemical ionization (PCI), and negative ion electron capture (NIEC) mode for qualitative identification or for isotope dilution quantitation in conjunction with heavy isotope-labeled standards.
  • Collaborative assistance with and instruction in extraction, purification, and derivatization of volatizeble organic molecules in preparation for GC/MS analyses in various ionization modes.
  • Assistance with synthesis of heavy isotope-labeled small organic molecules for use as internal standards in quantitation of target analytes or assistance in identification of commercial sources for such materials.
  • Assistance with identification of unknown molecules from biological extracts by GC/MS in various ionization modes, ESI/MS, and ESI/MS/MS and interpretation of mass spectra.
  • GC/MS analyses in various ionization modes (EI, PCI, NIEC) of sterols and their oxidation products for qualitative structural identification of quantitation in conjunction with internal standards.
  • GC/MS analyses in various ionization modes of derivatized amino acids and their oxidation products for qualitative structural identification or for quantitation.
  • GC/MS analyses of derivatized amino acid mixtures or fatty acid mixtures resulting from administration of heavy isotope labeled precursors to determine isotopic enrichment of [13C] or [2H] at high enrichment levels.
  • GC/MS analyses in various ionization modes of polyols, e.g. sorbitol, myo-inositol, chiro-inositol, and galactitol, and of other carbohydrates for quantitation.
  • CC/MS analyses of derivatized mixtures of heavy isotope labeled species of glucose to determine isotopic enrichment for the purposes of determining rates of glucose production and disposal in vivo.
  • Gas-on-line-combustion (or combustion/reduction)-isotope ratio mass spectrometry (IRMS) of [13C] or [15N] isotopic enrichment at low levels in derivatized amino acids obtain from hydrolysates of biological proteins to determine rates of incorporation into and disappearance from tissues.
  • Isotope ratio MS analyses of [13CO2] enrichment in exhaled breath samples as one parameter of isotopically labeled substrate disposition in vivo.
  • Isotope ratio MS analyses of doubly labeled [2H]/[18O] water samples to determine energy expenditure in vivo.
  • LC/ESI/MS and ESI/MS/MS of peptides from protein hydrolysates to achieve identification of proteins and their post-translational modifications, and collaborative assistance in learning to perform and interpret such analyses.
  • Matrix assisted laser desorption ionization (MALDI) time of flight (TOF) MS analyses of peptide mixtures from proteolysates for identification of proteins and their post-translational modifications, and collaborative assistance in learning to perform and interpret such analyses.
  • Training in the operation of GC/MS, IRMS, ESI/MS, LC/ESI/MS, ESI/MS/MS, LC/ESI/MS/MS and MALDI/TOF/MS systems for diabetes investigators, their technical staff, and their trainees.
  • Maintenance of functional GC/MS, IRMS, ESI/MS, LC/ESI/MS, ESI/MS/MS, LC/ESI/MS/MS, and MALDI/TOF/MS systems for use by diabetes investigators, their technical staff, and their trainees.
  • Instruction in the principles of various modes of MS and their applicability to analyses of biological samples and in the preparation of samples for MS analyses.
  • Providing a forum in the Mass Spectrometry Discussion Group seminars for presentation and discussion of results by diabetes investigators in studies requiring use of core facility instruments pertaining to the pathogenesis, complications, or treatment of diabetes.