The Preparation Of Molecularly Imprinted Polymers And Application In Enrichment Of Trace Acrylamide In Potato Chips

Acrylamide is a small unsaturated amide molecule,which mainly formed during heating of starchrich foods at high temperatures by maillard reaction and existing widely in all kinds of the foods.Furthermore,widely applied in water treatment industry also increase the exposing risks of population.Recent investigations have revealed that cumulative exposure to acrylamide mainly led to nervous system damage,the early clinical system of neurasthenia,such as dizziness,insomnia and hypodynamia,the later clinical symptoms included extremity numbness and ache paresthesia.Meanwhile,the animal experiments discovered that acrylamide has reproductive toxicity,genotoxicity and potential carcinogenicity.Based on the trace residue of acrylamide in food processing and environment and the complexity of the detection matrix,it is necessary to establish a specific sample preparation method for trace acrylamide so as to achieve target enrichment detection effectively.The sample pretreatment methods of rapidly enrichment and concentration were development based on surface molecularly imprinted technique,the principal researches and conclusions were as follow:（1）Acrylamide magnetic molecularly imprinted polymers（MPS-magnetic molecularly imprinted polymers,MPS-MMIPs）were successfully prepared by integrating surface imprinting and nanotechnology which have a good specific adsorption capacity towards acrylamide.Among them,acrylamide was used as template molecule and Fe₃O₄nanoparticles modified with silane coupling agent were served as supports.The results showed that transmission electron microscopy（TEM）and the Fourier Transform infrared（FT-IR）spectroscopy indicated that MPS-MMIPs were successfully synthesized;adsorption progress between AA and MPS-MMIPs followed pseudo-second-order reaction kinetics and Freundlich equation adsorption isotherm with equilibrium time at 60 min,moreover,the imprinting factor（3.22）of the MPS-MMIPs for AA was higher than that of nicotinamide and N,N’-Methylenebisacrylamide（1.13 and 1.36,respectively）in selectivity evaluation.These results demonstrated the MPS-MMIPs with super paramagnetic core-shell nanoparticle as the supporter had good mass transfer efficiency and specificity.（2）Propionamide（PA）,the structural analogs of acrylamide was used as dummy template molecule and the Fe₃O₄ nanoparticles modified with carboxymethyl dextran were developed as supports to synthesis acrylamide dummy magnetic molecularly imprinted polymers（dex-dummy magnetic molecularly imprinted polymers,dex-DMMIPs）.While acrylamide was also used as template molecule to comparison the adsorption properties of two different template molecularly imprinted polymers.The results showed that the adsorption of dex-DMMIPs reached equilibrium within 20 min,the static and selective adsorption experiment indicated that dex-DMMIPs had good binding capacity(Q_m=7.94mg·g^-1)and selectivity for acrylamide（α=4）.Moreover,the satisfactory recoveries of83.9-96.8%and relative standard deviation（RSD,n=3）of 1.42-6.98%were achieved for selective separation and enrichment of AA in spiked potato chips by dex-MMIPs.The simultaneous possession of high affinity and specificity by adsorption experiment determines dex-DMMIPs could be used as an adsorbent for acrylamide from complicated matrices like potato chips.（3）The acrylamide dummy molecularly imprinted polymers were successfully synthesized based on surface molecularly imprinted method on the surface of modified filter paper which propionamide used as dummy template molecule,methacrylicacid（MAA）and ethyleneglycol dimethacrylate（EGDMA）were chosen as the functional monomer and cross-linker,respectively.Scanning electron microscope（SEM）showed that acrylamide dummy molecularly imprinted polymers were loose and porous in the surface of filter paper.Meanwhile a series of adsorption experiments were carried out to study the adsorption properties,the kinetics study showed the adsorption of polymers reached equilibrium within30 min and the adsorption processes followed the pseudo-second-order kinetic models;static adsorption experiment indicated that the maximum adsorption quantity（Q_m）were60.82 mg（piece）calculated by scatchard model and the adsorption processes followed the Freundlich isotherm.Moreover the paper molecularly imprinted polymers were applied in the determination of acrylamide from potato chips,yielding satisfactory recovery（88.60-95.90%）and low relative standard deviation（2.30-7.87%）.Thus,the acrylamide paper molecularly imprinted polymers were demonstrated to be convenient and practical sample pretreatment materials for the concentration and separation of acrylamide from food samples.