Studies On The Detection Methods Of Melamine In Feed

Since the the U.S. pet food and Sanlu milk powder incident in our country outbreak of, how to control and eliminate the source of illegal melamine added, has become the focus of everyone’s attention. In order to ensure the quality of feed products to protect the safety of stockbreeding and animal products, based on the large number of animal tests and validate risk assessment, the Ministry of Agriculture with effect from June8,2009onwards, feed ingredients and feed products, melamine limited value as a2.5mg/kg, above this level of feed ingredients and feed products may not be sold. Monitoring of the source from the livestock and poultry breeding illegal use of melamine, in order to provide a basis for law enforcement in agriculture is of great significance. This laboratory feed melamine detection method was studied. Using isotopic internal standard and gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure melamine in animal feed.Isotopic internal standard and gas chromatography-mass spectrometry(GC-MS) method has been established for the determination of melamine in animal feed. Extracted with the solution of trichloroacetic acid and lead acetate, the samples were cleaned by PCX SPE columns, derived with BSTFA and dissolved, before detected by GC/MS and isotopic internal standard method. The limit of detection(LOD) of melamine in feed was50μg/kg, and the linearity of melamine was within the range of125ng/mL～5000ng/mL. The mean recovery of melamine in formula feed, concentrated feed and premix was95.0%,95.6%and94.9%, and the mean RSD was2.8%,3.3%and3.7%, respectively.A high performance liquid chromatography-tandem mass spectrometry method (LC-MS/MS) method has been established for the determination of melamine in animal feed. The samples were extracted with the solution of trichloroacetic acid and lead acetate, cleaned by PCX SPE cartridges and separated through a HILIC column.Mass spectrometry condition: electrospray ionization(ESI+) and selected reaction monitoring(SRM) mode. The detection used15N3-melamine as the isotopic internal standard. The limit of detection(LOD) of the method was1μg/kg. The calibration curve has good linear within the range of ribavirin concentration from1ng/mL to50ng/mL. The mean recovery of melamine in formula feed, concentrated feed and premix was97.5%,98.9%and98.0%, and the mean RSD was4.3%,4.1%and4.3%, respectively. Compared with the external standard method, the method was accurate and reliable in quantification, and it was more propitious to be used for the quantitative determination of melamine in feed.