PROJECT SUMMARY This proposal requests funds for an integrated mass spectrometry system consisting of SCIEX 7500 triple quadrupole mass spectrometer with QTRAP functionality (AB Sciex LLC, Framingham, MA USA) along with a Nexera UPLC (Shimadzu, Kyoto, Japan), SCIEX gas generator, uninterruptible power supply, and workbenches. The requested instrument will be located in and maintained by the Eicosanoid Core (EC) at Vanderbilt University Medical Center. This instrument will used to measure bioactive oxidized lipid mediators. Three major users and four minor users from across three different divisions within the Department of Medicine, the Department of Ophthalmology and Visual Sciences, and the Vanderbilt University Department of Pharmacology will use mass spectrometry to study the role of these important signaling molecules in cancer, diabetes, diabetic retinopathy, cardiovascular disease, hypertension, and more. The ability to identify and differentiate between many structurally related oxidized lipid mediators at low concentrations in biological samples is critical to understanding the role of these important signaling molecules in human physiology and disease response. Due to the carboxylic acid functionality on all oxylipins, these molecules ionize best in the negative ion mode, but negative ion electrospray MS has traditionally suffered from low sensitivity. The source design of the SCIEX 7500 has been tailored to enhance ion detection, particularly for negative ions. Oxidized lipid mediators show peak areas more than 50x higher using the SCIEX 7500 compared to the previous generation instrument. Test samples sent to SCIEX from the EC detected 48 oxylipins, while only 29 oxylipins were detected using the LC/MS system that is currently leased by the EC. In addition to sensitivity gains, the SCIEX 7500 is equipped with QTRAP functionality, which adds greater specificity. The QTRAP allows the third quadrupole in this system to be configured as a Linear Ion Trap. While quantitative data is being collected using the MRM mode, enhanced product ion scanning can be captured, obtaining structural information of the detected analyte. This feature is particular useful for the detection and accurate assessment of oxylipins, as many structurally distinct oxylipins and related metabolites have the same mass-to-charge ratios and similar structures. The overall added sensitivity and specificity of the SCIEX 7500 will significantly enhance the capabilities of the users to detect and quantify oxylipins in low-level biological samples. This location of the EC is in close proximity to the laboratories of many of the users. Dr. Milne, Director of the EC, is a world-renowned expert in the analysis of oxidized lipid mediators and has extensive training and experience in mass spectrometry. Personnel in the ECL have combined more than 120 years of experience in assisting more than 200 investigators worldwide with mass spectrometric analysis of lipid mediators. Instit...