HPLC Retention of Sulfamic Acid on Zodiac HST SB Mixed-Mode Column

Sulfamic acid is an inorganic acid commonly used in various syntheses and formulations, including as a precursor in the production of artificial sweeteners. Also known as amidosulfonic acid, amidosulfuric acid, aminosulfonic acid, and sulfamidic acid, it is highly hydrophilic and does not retain on traditional reversed-phase columns. Due to its acidic properties, sulfamic acid can be effectively retained using mixed-mode chromatography. In this method, the ZodiaC HST SB mixed-mode anion-exchange column is used to retain sulfamic acid via anion-exchange interactions. The method utilizes acetonitrile in combination with ammonium formate or formic acid. As sulfamic acid lacks UV absorbance, detection is performed using LC/MS, ELSD, or Corona CAD. Retention time can be fine-tuned by adjusting the concentration of buffer or acid in the mobile phase. This approach is well-suited for analyzing both organic and inorganic acids in various sample types.