Though methanol is the most common used eluent in RP-HPLC, it is not of suitability for HILIC mobile phase (Hemstrom & Irgum, 2006). In this work, acetonitrile was demonstrated suitable for elution of melamine, whereas methanol resulted in bad resolution between the un-retained components and melamine. The retention time of melamine increased with the percentage of acetonitrile in the mobile phase (Table 1), and when the percentage of acetonitrile was less than 70%, melamine was weakly retained in the amino column. Considering both the rational retention time (adequate
separation of melamine from other components without unnecessary extending of the run time) and the hydrophilicity of the
mobile phase, 88% of acetonitrile was chosen for the separation