During the AOAC Annual Meeting held in Las Vegas, NV from September 30 to October 3, 2012, the Stakeholder Panel on Infant Formula and Adult Nutritionals convened to review single-laboratory validation data submitted for the method, Vitamin C in Adult/Pediatric Formula by Ultra-Performance Liquid Chromatography with Ultraviolet Detection. This method is a modified version of the method "HPLC-UV Determination of Total Vitamin C in a Wide Range of Fortified Food Products" previously published in Food Chem., 94, 626-631 (2006). The SLV data from the modified method were reviewed and compared to the standard method performance requirements (SMPR 2012.012), and it was concluded that the method meets the requirements. The method was approved as AOAC Official First Action. The method is based on the acidic extraction of ascorbic acid in the presence of Tris[2-carboxyethyl] phosphine (TCEP) as a reducing agent. Separation was achieved on a C18 column with a sodium acetate eluent (pH 5.4) combined with TCEP and decylamine as an ion-pairing agent. Accuracy rates were between 90 and 100%. Repeatability RSD (RSD,) ranged from 1.4 to 2.5%, and intermediate reproducibility RSD (RSDiR) ranged from 1.3 to 7.5%.