Analytical Unit

Manager & Lead Scientist
Besim Ogretmen, Ph.D.
Professor, Biochemistry & Molecular Biology | 843-792-0940
Barbara Rembiesa, BS | 843-792-7726
Jason Pierce, MS | 843-792-7726
Aiping Bai, Ph.D. | 843-792-7726
Silva Terzieva, Ph.D. | 843-792-7726
Shared Resource Locations
Analytical Unit - 505C Children's Research Institute
Synthesis Unit - 748/747B - Basic Science Building


  • Qualitative (compound identification) and quantitative LC-MS/MS analysis of the key lipids from different biological materials (cells, tissues, serum, blood) determining their basal levels and changes in response to exogenous agents.
  • Analyses of ~350 different sphingolipid and DAG components at a basic metabolomics level.
    Metabolomic Profiling of Sphingolipids (PDF)
  • Methodology for the study of sphingolipid metabolism, thus eliminating the use of radioactive precursors (cell labeling with 17C sphingolipids and LC-MS/MS combined approach for analysis).
  • Methods for the determination of enzymatic activities at the cellular level (using 17C sphingolipids: e.g., 17C-Sph and LC-MS/MS combined approach for SK activity).
  • Determination of enzymatic activities of lipid metabolizing enzymes in vitro and ex vivo.


The Analytical Unit has the following equipment:

  • Four (4) chromatography/mass spectrometer instruments with either ultra-high pressure HPLC systems or a supercritical fluid chromatograph (SFC) instrument. These instruments are capable of dual ionization mode, electrospray ionization (ESI) and/or atmospheric pressure chemical ionization (APCI).
  • Nitrogen generator.
  • Savant speed-vacuum evaporator.
  • Two (2) nitrogen evaporators.
  • Beckman centrifuge.
  • Shimadzu UV-1601 spectrophotometer.
  • Microbalance Metler Toledo.

Data Presentation

Analytical results should be expressed as one of the following:

  • Lipid level (pmol) / Protein level (mg)
  • Lipid level (pmol) / Phospholipid level determined from the Bligh & Dyer lipid extract (nmol)
    Bligh, E .G., Dyer, W.J., (1959) A rapid method of total lipid extraction and purification. Can. J. Biochem. Physiol. 37, 911-917.
  • Lipid level (pmol) / Volume (µL) reflecting in molar concentration [M].
  • Lipid level (pmol) / Tissue weight (mg).

Reference Citation

The following text on lipid analyses by HPLC-MS/MS must be placed under the Methods Section of manuscripts:

“Sphingolipid levels were measured by high-performance liquid chromatography mass spectrometry (LC-MS/MS) methodology as previously described. Bielawski, J., Pierce J.S., Snider J., Rembiesa B., Szulc Z.M., Bielawska A. (2009) Chapter 22 Comprehensive Quantitative Analysis of Bioactive Sphingolipids by High-Performance Liquid Chromatography–Tandem Mass Spectrometry, In D. Armstrong (Ed.), Lipidomics: Vol1: Methods and Protocols (pp. 443-467) New York, NY: Humana Press, a part of Springer Science+Business Media, LLC (Methods in Molecular Biology, Vol.579, ISBN: 978-1-60761-321-3)”

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