Assessing sialic acid content in food by hydrophilic chromatography-high performance liquid chromatography

We have established a novel hydrophilic chromatography (HILIC)-high performance liquid chromatography (HPLC) method to assess sialic acid content in food products. Single-factor and response surface methodologies (RSM) were used to systematically optimize the hydrolysis conditions of the food samples to extract the maximum amount of sialic acid. Chromatographic conditions were also adjusted. In foods containing sialic acid, we observed a strong linear relationship between sialic acid and peak area, ranging from 5 to 100 μg/mL (R² = 0.9998). The lowest detectable sialic acid concentration (RSN = 3) was 0.2 μg mL⁻¹, and the method detection limit was 0.02mg kg⁻¹. Sample recovery ranged from 95.85% to 99.78%, with an RSD of 1.46% (n = 6). Thus, the described method can be applied to the study of sialic acid content in foods.