Using sweeping-micellar electrokinetic chromatography to determine melamine in food

This study developed a sweeping-micellar electrokinetic chromatography (sweeping-MEKC) method for fast screening of melamine in food. In order to optimise parameters with multiple responses in parallel, face-centred cube central composite design (FCD) was employed to search for the optimum conditions of the sweeping-MEKC. The optimum background electrolyte was composed of 45 mM phosphoric acid and 175 mM sodium dodecyl-sulfate with the addition of 15% (v/v) methanol. Under such conditions, melamine content could be determined within 13 min with the limit of detection (S/N = 3) at 5 ng/mL. The developed method was validated by analysing melamine-spiked milk, gluten, chicken feed, and cookies. The proposed method was applied to determine melamine in different food products, with recoveries between 92.9 ± 3.3% and 108.4 ± 1.7%. The present study shows that the developed sweeping-MEKC method is sensitive, accurate, and efficient for fast screening of melamine in food.