Caffeine and benzoic acid are found in many beverages. Diet beverages use calorie-free artificial sweeteners to replace sugar. While saccharin was the first artificial sweetener, aspartame is the most common. Concentrations for each analyte were found in six samples. The samples include Coke Zero, Diet Coke from a can, Diet Coke from a fountain, TaB, a glass of water with Sweet n’ Low, and Nestle Diet Tea. The concentrations were found by constructing a calibration curve from mixed standards using the HPLC