The objective of this application is to strengthen our programs of research in age-related, inflammatory and infectious diseases by acquiring a hybrid triple quadrupole linear ion trap mass spectrometer. The acquisition of a new LC-MS/MS instrument will benefit a main user group of six principal investigators affiliated with the Environmental Health Sciences Center (EHSC) and the Center for Healthy Aging Research (CHAiR) at Oregon State University (OSU). The NIH-funded driving biological projects behind this application involve fundamental studies on the interaction between biological oxidants and proteins, lipids, vitamins, and dietary phytochemicals. They are focused on (1) the role of peroxynitrite-mediated tyrosine nitration in amyotrophic lateral sclerosis, (2) the role of oxidative stress on ceramide turnover in cardiac mitochondrial aging, (3) the identification of novel dietary phytochemicals for the prevention of prostate cancer, (4) the role of lipid peroxidation-mediated damage to mitochondrial proteins in cardiac aging, (5) the role that ascorbylation of lipid peroxidation products plays in the prevention of atherogenesis, and (6) the effects of vitamin E and its metabolites on hepatic metabolism of drugs and other xenobiotics. The requested instrument will also support a secondary user group of five NIH-funded faculty and five NIH-funded occasional users at OSU. The advantages of the requested instrument compared to our existing PE Sciex API III Plus mass spectrometer are (1) the significantly higher sensitivity for quantitative analysis, (2) a better collision cell that allows quantification of hundreds of analytes in complex biological matrices during a single chromatographic run, (3) increased sample throughput due to a different vacuum pumping system that needs no overnight recycling, and (4) a more modern data acquisition and data processing computer system. The unique feature of enhanced product ion scanning of the linear ion trap can provide a wealth of structural information for the identification of small biological molecules and their metabolites in extracts of plasma, cells and cell organelles, which is an important focus of the main driving biological projects. Rapid switching between the negative and positive ion modes in combination with precursor ion, neutral loss, and product ion scanning on the hybrid instrument will provide an extremely powerful tool for mapping phosphorylation sites and other post-translational modifications of proteins in the research activities of three NIH-funded investigators. [unreadable] [unreadable]