Fast separation and analysis of Sudan dyes in chili products by molecular imprinted-matrix solid phase dispersion

Molecularly imprinted polymer ( MIP) was synthesized by surface imprinting technology using nano SiO2 as supporter, Sudan IV as template, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker. The isothermal absorption experiment and kinetics absorption experiment of MIP were applied. 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 Kd were as follows: Qmax1= 0.8306 mg /g, Kd1= 4.760 mg /L, Qmax2= 4.146 mg /g, Kd2= 112.4mg /L.The results of kinetics absorption experiment revealed that the absorption of MMIP for Sudan IV was conforming to pseudo-second order absorption model.The prepared MIP was used as the sorbent of matrix solid phase dispersion to analyze the Sudan Ⅰ, Ⅱ, Ⅲ and Ⅳ in the chili powder. The experimental conditions were optimized: the ratio of MMIP and sample was 1∶1, milling time was 8min, and the eluent was 4mL of 5% acidified ethanol.This method possesses was not only the high selectivity of molecularly imprinting technology, but also the fast separation of matrix solid phase dispersion method.