2007 Annual Report 1a.Objectives (from AD-416) Develop an analytical method for determination of Vitamin D in foods. 1b.Approach (from AD-416) Use liquid chromatography-mass spectrometry with stable isotope dilution to determine Vitamin D2, D3, 25-OH D2, and 25-OH D3. 3.Progress Report This report documents research conducted under a reimbursable agreement between ARS and the Office of Dietary Supplements at the National Institutes of Health. Additional details of research can be found in the report for the in-house associated project 1235-52000-058-00D, “Liquid Chromatographic and Stable Isotope Dilution Mass Spectrometric Methods for the Determination of Water-Soluble and Lipid-Soluble Vitamins in Foods and Dietary Supplements.” A training grant from the Office of Dietary Supplements was approved for funding from October 1, 2005 through September 30, 2007 (i.e. FY 2006 and FY 2007). The post-doctoral research associate hired to fill the position left the Food Composition and Methods Laboratory at the end of FY 2006 to take a position in industry. Since the grant was specific to the trainee, the agreement has been terminated. This agreement was monitored through routine conversations and e-mails with scientists from the Office of Dietary Supplements. 4.Accomplishments None. 5.Significant Activities that Support Special Target Populations None.