HPLC Determination of Melamine in Feed and Raw Milk

Condition used in the GB/T 22400-2008 were applied to the analysis of feed for its melamine content,thus avoiding the operation of changing chromatographic column and mobile phase.The SCX column (250 mm×4.6 mm,5 μm) was used as stationary phase (column temp: 30 ℃),and a mixture of KH2PO4 buffer solution of pH 3.0 and acetonitrile (mixed in the ratio of 7 to 3 by vol.) was used as mobile phase in the elution at the flow-rate 1.0 mL·min-1.UV detection with DAD at the wavelength of 240 nm was adopted in the determination.Range of linearity for melamine was found between 0.5 mg·L-1 and 10.0 mg·L-1.Detection limit (3S/N) found was 2.0 mg·kg-1.Recovery and precision were tested at 3 concentration levels of 2.0,5.0,10.0 mg·kg-1,by addition of standard melamine solution to a same matrix sample.Values of average recovery found were in the range of 78.8% to 80.1% with values of RSD′s (n=6) less than 8.10%.