Absolute and Relative Quantitation for Targeted Metabolomics and Lipidomics

The ultimate goal of targeted metabolomics and lipidomics is to report absolute metabolite and lipid concentrations. The Agilent Metabolomics dMRM Database and Method is a supported solution for 219 central carbon metabolites in negative ion mode. It is a fully tested rugged method that provides incredibly stable retention times across large numbers of samples with excellent inter-day and extended (over 4000 biological samples) retention-time reproducibility.

IDMS gets rid of Ionization suppression effects as well as any bias from sample preparation and instrument conditions. The only downside is the cost and availability of isotopically labeled internal standards, especially in an assay with 219 metabolites. We have circumvented the cost of purchasing individual internal standards by using 13C incorporated yeast from Cambridge Isotope Labs. These cells are grown in 13C enriched media and the resulting metabolites in the extract have >99% isotopic enrichment. Using this technique, we show linearity for fragile metabolites over six orders of magnitude ranging in most cases from attomole to nanomoles concentrations on column.

We will also present the method and results for targeted lipidomics with the use of deuterated internal standards that covers a wide range of lipid classes.

For Research Use Only. Not for use in diagnostic procedures.

Presenter: Sheher Banu Mohsin, PhD (Senior Applications Scientist, Agilent Technologies, Inc.)

Sheher Mohsin is a senior applications scientist at Agilent Technologies. She received her Ph. D in physical chemistry from the University of Illinois and an MBA from Rockhurst University. She started her career at the US Environmental Protection Agency working on dioxin analysis with high resolution mass spectrometers. She later joined Bayer and worked in the special analysis lab using mass spectrometry to solve problems in synthesis, impurity determination and submission of final product impurity profile to regulatory agencies. Sheher’s current focus is on lipidomics using GC, LC and SFC separations and mass spectrometry. Sheher collaborates with academic and government researchers working on complex problems to come up with innovative, simplified workflows using the latest tools in separation and mass spectrometry.