Lipids are intermediates in energy metabolism, structural components of biological membranes and as intra- and extra- cellular signals. Aberrant lipid metabolism plays a central role human pathophysiologies, including cardiovascular disease, obesity, diabetes, and cancer Systems-level analysis of lipids has lagged behind rapid progress in genomics and proteomics. Newly developed analytical approaches using tandem liquid chromatography and multi- dimensional mass spectrometry have spawned the field of "lipidomics"- a focused area of metabolomics that concerns the systems-level analysis of lipids and lipid-dependent processes. As a component of a core laboratory of our Center for Research on Obesity and Cardiovascular Disease, the University of Kentucky operates an ABSciex 4000 Q-Trap hybrid triple quadrupole linear ion trap mass spectrometer which is used primarily for analysis of lipids and lipid-related molecules including glycero and sphingo phospholipids, fatty acids, ceramides, sphingomyelins, sterols and cholesterol esters, di and tri glycerides, acyl carnitines, oxidized lipids and their reaction products, peptide hormones, arachidonic acid derived signaling molecules and their metabolites by HPLC, electospray ionization (ESI) selective reaction monitoring mode tandem mass spectrometry. In addition to its ability to operate as a component of a triple quadrupole mass spectrometer, the Q3 mass analyzer of this instrument can function as a linear ion trap conferring significant additional capabilities to the instrument that make it an extremely powerful tool for metabolite identification. While the HPLC configuration for sample separation and introduction using a high flow Turbo V ESI ion source is ideal for analyte quantitation by selective reaction monitoring, this arrangement is not compatible with newly developed powerful strategies for lipid profiling. This is because it is often difficult (or not possible) to separate the sometimes greater than 30-50 distinct lipid molecular species within a given class by column chromatography so narrow peak widths limit the time the instrument has to conduct scans to identify components of closely eluting lipid species. Methods that address this limitation mandate direct sample infusion allowing the instrument to identify lipid species conducting a series of lipid class specific precursor ion or neutral loss scans. Because of issues of sensitivity, sample availability and analyte abundance, detection of lipids in these experiments is greatly enhanced by low flow (10-200 nl/min) infusion of small volumes of concentrated samples. The purpose of the present application is to request funds to upgrade the instrument with an Advion Nanomate Triversa automated chip infusion system and an ABI Nanospray III ion source. This upgrade will allow us to use our instrument for lipid profiling studies by automated nanospray ESI mass spectrometry using these newly developed platforms for instrument operation and data analysis.

S10RR026884

2011-05-01

2012-04-30