Separation and analysis of melamine in milk powder by mesoporous molecular imprinted polymers

Mesoporous molecular imprinted polymers( MIP) was prepared by Sol- Gel technique using cyromazine as virtual template molecule. The MIPs used as solid phase extraction adsorbents were coupled with high performance liquid chromatography( HPLC) to detect melamine in milk powder samples. The results of isothermal absorption experiment and Scatchard analysis showed that there were two kinds of binding sites. By calculating,the values of the apparent maximum absorption capacity Qmaxand the dissociation constant Kdwere as follows:Qmax1= 14.96 mg / g,Kd1= 1.85 mg / L,Qmax2= 26.16 mg / g,Kd2= 27.03 mg / L. The melamine in 2 g milk powder samples was purified and enriched by MIP. The recovery of melamine was between 94.73% and 98.56%,relative standard deviation( RSD) was 3.2%,and the detection limit was 0.015 μg / g. This method was rapid and high selectivity,and provided a new way to analyzing residue melamine.