Determination of Melamine in Food by SPE and CZE with UV Detection

A novel method for the determination of melamine residue in food was developed using solid-phase extraction and capillary zone electrophoresis with UV detection. Spiked samples were extracted with 1% trichloroacetic acid while 0.03 g sodium deoxycholate was used to precipitate protein in the real samples. After centrifuging and clean-up by solid-phase extraction cartridge, the extract was directly analyzed by CZE-UV. The method was validated and good results were obtained with respect to precision, repeatability and spiked recovery. The limit of detection for melamine varied between 0.25 and 0.5 mg kg(-1). The proposed method was successfully applied for the analysis of melamine in food with total recoveries ranging from 94 to 102% in the spiked range of 0.5-5 mg kg(-1), and the relative standard deviations were between 1.5 and 4.1%.