The Biomarker Mass Spectrometry Facility supports research on the UNC-Chapel Hill Campus by providing mass spectrometric identification, characterization and quantitation of biomarkers of exposure. The Biomarker Mass Spectrometry Facility seeks funding to acquire an ultra-high performance bench top triple quadrupole LC-MS/MS system. Our need for the requested instrument is two-fold. Currently the instruments operated by the Biomarker MS Facility are operating around the clock (except for instrument down-time and maintenance) and analyses require four or more weeks advance scheduling. The current volume of demand for the Facility's analytical services exceeds our capacity, resulting in delays in scheduling analyses and leaving no leeway for new projects that are being initiated as assays for DNA damage which we have developed are being transferred to other users on campus. Our other pressing need is for higher-sensitivity analysis than can be provided with the current instrumentation. Because we are measuring analytes which are present at low levels in samples such as human tissue which are available in very limited quantity only, we need sensitivity of detection well beyond what can be achieved with the instruments currently operating in the facility. We therefore seek an instrument with LC-MS/MS, high-throughput capability and high sensitivity. We also need this instrument to accept nano and capillary LC input. This instrument will support research into cisplatin DNA adducts, lipid composition, molecular dosimetry of DNA adducts derived from butadiene, ethylene oxide, propylene oxide and isoprene, and studies on choline metabolism, cancer causality and susceptibility, DNA damage and repair, molecular epidemiology, exposure assessment, and other healthrelated topics. The instrument of choice is an Applied Biosystems/MDS Sciex API 4000 interfaces with an LC Packings (Dionex) capillary/nanoflow high pressure liquid chromatography system. This instrument will be installed in an established and productive shared-use facility staffed by experienced personnel, where it will support the research of ten holders of eleven current or pending R01 and U01 NIH grants.