Amino acids are a group of chemically diverse organic compounds. The amino acid composition will determine the quality of polypeptides or proteins. As the requirements defined by the United States Pharmacopeial Conventin (USP), European Pharmacopoeia (Ph. Eur.), and other regulatory agencies, the qualitative and quantitative composition of medicines has to be determined. Therefore, it is essential and necessary to quantify and identify biopharmaceutical active ingredients, and determine impurities and related substances in active pharmaceutical ingredients.