Types of Analysis

In the last decade or two, advances in mass spectrometry allow it to be applied to quantitative and qualitative analysis of compounds that are volatile or involatile. Modern separation methods combine in powerful ways with mass spectrometry.

Proteomic analysis

Proteomic approaches have enabled the identification of thousands of differentially expressed proteins in complex mixtures and also ushered the capability of discriminating disease subtypes/aggresiveness that are not recognised by traditional criteria.  Thus, it offers a platform for the identification and quantification of proteins and may uncover new therapeutic targets.  Translation of protein biomarkers in FDA approved diagnostic can be carried out at BMSF.

Metabolomic Analysis

While electron ionisation (EI) coupled with GC/MS is the main technique for volatile compounds, the BMSF has expertise in a particularly sensitive and selective method based on negative ion mass spectrometry. This involves tagging the molecules of interest with a group that makes those molecules capture electrons and so form negative ions. The fragmentation data generated can be compared to the Wiley and NIST MS libraries.

The electron capture negative ion MS technique (ECNI MS) can be used effectively for many metabolite/marker and clinical mass spectrometry studies. Polar small molecules (involatile) are analysed by LC/MS (see below) using ionisation methods such as ESI and APCI. These methods are often useful in environmental analysis, metabolite analysis etc.

Many biologically relevant and pharmacological compounds that are too thermolabile for direct gas chromatography (GC) can be derivatised to their trimethylsilyl esters and ethers, then identified.

Small Molecules and Headspace

Our small molecule analysis work includes accurate mass analysis with mass-to-charge measurement accuracy of 2ppm using an LTQ-Orbitrap XL MS with static nanospray.  This is used to confirm synthetic target structures and to narrow the range of possible elemental formulae for unknowns.  Isotopic fine structure dta for unknowns can also be determined.

Volatile organic compounds (VOC's) in the headspace above aqueous sample solutions can also be determined by both direct headspace sampling and by solid phase microextraction (SPME).  Typical applications include odor analysis, novel cancer screening technologies, quantifyinig methanogenesis in the headspace above cultured bacteria and analysis of permanent organic and inorganic gases.

Lipidomic analysis

Lipids have low water solubility and comprise a broad range of structurally diverse molecules, including fatty acids, waxes, eicosanoids, monoglycerides, diglycerides, triglycerides, phospholipids, sphingolipids, sterols and steroids, terpenes, prenols and fat-soluble vitamins.  Lipids are commercially important as food, in the production of biodiesel and other manufacturing processes, and they perform a wide variety of biological functions.

Key roles include energy storage, cell membrane structure and signalling molecules.  Considerable research demonstrates that changes in lipid species and lipid damage significantly influence the development of disease by a range of mechanistic pathways.

Isotope Ratio Mass Spectrometry (IRMS)

The BMSF has capabilities for the stable isotope analysis of carbon and oxygen isotopes for small inorganic carbonate samples, such as used in the analysis of stalagmites, coral, and bone apatite. Applications include environmental sciences, geosciences, forensic science, and archaeological sciences, measured using a MAT253 and Kiel IV carbonate device.

We also have compound specific and bulk organic isotope capabilities for carbon, nitrogen, oxygen, and hydrogen isotopes.

Our HTEA-GM-IRMS has a wide range of environmental and forensic applications, including tree cellulose records of environmental change, environmental lipids and food web studies, and the analysis of archaeological collagen.

Desorption Electrospray Ionisation (DESI)

The DESI technology is a simple, sensitive, gentle, and versatile ionization method that allows for the direct sampling of surfaces without any sample preparation and under ambient temperature and pressure conditions. This patented technology (patent #7335897) was first disclosed in Science, Vol. 306, #5695, pp. 471-473, October 2004. (see http://www.prosolia.com/omnispray.php).