Small Molecules Characterization and Quantitation Using HPLC-MS and GC-MS
Capitalizing on a two-decade long experience of the lab members with lipids and other small molecules, the Metabolomics facility offers services related to the evaluation of the composition of complex biological samples such as cells, skin and ocular tissue extracts. The samples can be analyzed using a range of approaches which include, but are not limited to, thin layer chromatography (TLC), GC, HPLC, and various types of mass spectrometry. Other approaches can be considered as well.
The samples are to be provided by participating researchers in the form of extracts dissolved in proper organic solvents (typically, methanol, propanol, chloroform, hexane, or acetone). The required amounts will depend on the putative composition and complexity of the mixtures, and stability of the analytes. The Module staff will assist the researchers in devising proper strategies to prepare samples suitable for analyses.
The samples will be evaluated to identify individual components in the mixtures, and to estimate their ranges. This is routinely done by using the direct infusion (DI) approach (no chromatographic step involved). During the DI step, the presence of interfering factors (such as exogenous contaminations) will be evaluated.
Depending on the results of the DI analyses, a proper chromatographic technique will be chosen to:
- Ensure adequate separation of analytes from interfering compounds
- Optimize conditions of the analytical runs
Unknown analytes will be structurally analyzed using MS(n) approaches and compared with authentic standards (if available).
Compounds will be quantitated using HPLC/MS (if proper standards of the analytes are available).
Initially, analyses will be offered for lipids and lipid-signaling factors. In the future, we plan on expanding our services to include other types of low-molecular weight compounds and proteins.
2D and 3D Imaging of Tissue Sections (projected start of service 2Q 2016)
The recent advances in mass spectrometry led to development of Tissue Imaging Mass Spectrometry (TiMS) that makes it possible to create a 2D map of distribution of low molecular weight analytes in a thin tissue section, and by analyzing multiple stacked tissue slides – to recreate a 3D distribution of analytes of interest in a parent tissue. We are in the process of acquiring an Omni Spray DESI 2D ion source for our ThermoElectron LCQ Deca XP MAX and LCQ Fleet mass spectrometers, which would allow us to offer TiMS services in 2016.