Oligosaccharides, such as β-galactooligosaccharides (GOS), are often formulated in foods and beverages as prebiotics. AOAC Official Method 2021.01 provides a reliable way to determine the GOS content in infant formula by hydrophilic interaction liquid chromatography (HILIC). However, we uncovered a potential issue of adsorption in the HILIC of dextran oligosaccharides under the same HILIC conditions as those specified in AOAC Official Method 2021.01. Analyte loss and carry-over were observed for dextran with degree of polymerization (DP) of six and higher. This adsorption issue was effectively solved by using the MaxPeak^TM High Performance Surface (HPS), a hybrid surface technology that designed to mitigate metal analyte adsorption issues in liquid chromatography. There was no adsorption issue was found in the analysis of GOS, however, considering the structural similarity between dextran and GOS, it is prudent to use the MaxPeak HPS incorporated LC systems and columns in the HILIC analysis of GOS (AOAC Official Method 2021.01) to eliminate the potential risk of adsorption issue.