Determination of melamine in dairy products by HILIC-UV with NH2 column

A HPLC method using a NH2 column for determination of melamine was reported, with acetonitrile-H3PO4 (15 mmol L−1, pH = 6.5) (V/V = 88:12) as mobile phase and UV detection at 215 nm. The tested parameters included mobile phase composition, percentage of organic solvent, and buffer concentration, and pH value and UV detection wavelength. Good linearity was observed within the concentration range of 0.005-32 mg L−1 (n = 7, r = 0.9997), the detection limit was 0.003 mg L−1 (S/N = 3). The chromatography mode was considered to be hydrophilic interaction chromatography (HILIC). The method was successfully applied to determine melamine in several dairy products, with acetonitrile as extract solvent of melamine and also as protein precipitant. The spike recovery of melamine was within 73-96%.

► A NH2 column was used for separation of melamine, which was seldom reported. ► Acetonitrile was used as mobile phase component and protein precipitants, thus no other protein precipitant was needed. ► The present HILIC-UV method was more sensitive than most of the reported HPLC-UV methods.