PROJECT SUMMARY / ABSTRACT The S10 proposal seeks funding to purchase a new Agilent 8900 Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to replace our 14-year-old Agilent 7500 ICP-MS, which has been out of order since December 2020. The new ICP-MS will be housed in the Biomarker Mass Spectrometry Facility (BMSF), a shared UNC research facility that has successfully served the campus for over two decades. As an obsolete model, our 7500 ICP-MS was deemed unrepairable by Agilent service engineers. The 7500 ICP-MS, purchased with institutional funds in 2008, has been the workhorse equipment in the Facility and supported NIH grants totaling over $30 million in the last decade, demonstrating outstanding past performance of the ICP-MS at the BMSF to support funded research. The 7500 ICP-MS at the BMSF is the only shared ICP-MS resource on UNC campus. Unavailability of ICP-MS is very disruptive among our users and investigators, threatening the timely completion of active NIH-funded projects (~$18 million in next 5 years). Agilent ICP-MS remains best of its kind and Agilent 8900 ICP-MS has superb sensitivity and interference removal to enable the detection and quantitation of elements in diverse sample matrices with ultratrace levels of metals. The BMSF has great technical expertise in operating the ICP-MS, with a dedicated highly experienced research specialist. Dr. Lu, the Director of the BMSF, has over 15 years of experience in the mass spectrometry and metal analysis with ICP-MS, who has also established leadership in overseeing and managing research facilities/cores to support investigators in diverse fields. Selected 13 NIH-funded projects from 7 major (~76% AUT) and 3 minor users (~10% AUT), as outlined in this proposal, all have significant and urgent needs for state-of-the-art ICP-MS for sensitive elemental analysis. Our two decades of success has unequivocally established the BMSF as a key player in exposure measurement with ICP-MS. With everything in place at the BMSF, including unparalleled sensitive instrumentation, highly experienced personnel, a large user base, a strong leadership team and institutional commitment, the requested 8900 ICP-MS will continuously succeed as a valuable and unique resource to serve UNC and beyond.