Buffer-Free Ion Chromatography(BFIC) of Aspartame: Organic Modifier Effect

The effect of varying the acetonitrile percentage in the mobile phase is illustrated using a Zodiac HST C HPLC column in a Buffer-Free Ion Chromatography (BFIC) separation. As the acetonitrile content decreases, the retention time of the artificial sweetener Aspartame initially decreases and then increases. TThis shift indicates a transition in the retention mechanism—from a combination of hydrophobic and BFIC (Buffer free ion chromotography)interactions, to BFIC alone, and eventually to a mix of BFIC and hydrophilic interaction liquid chromatography (HILIC) mechanisms. Aspartame consists of two amino acids, aspartic acid and phenylalanine, in the form of an ethyl ester. The separation was achieved using mobile phases composed of water and acetonitrile (MeCN or ACN), with ultraviolet (UV) detection.