Preparation Of Sodium Saccharin Silica Surface Molecular Imprinted Polymers And Its Adsorption Behavior

In this paper, molecular imprinting technique is applied to the detection of sodium saccharin in food additives. First, research status in this area have been summarized,then introduced the principle, features, preparation method of molecular imprinting technology and the advantages and disadvantages of detection method of food sweetener currently.Experiment is consisted of three parts: in the first part acrylic is selected as a functional monomer by ultraviolet spectrophotometry. Using the St?ber way to synthesis monodisperse particles of Si O2 and characterize it by transmission electron microscopy, scanning electron microscopy, nano-size analysis. It shows that the Si O2 particles have an average particle size of 310 nm, are the nanoscale particles. Using surface molecular imprinting method to synthesize sodium saccharin molecular imprinted polymers in an aqueous environment with amino silica gel as a carrier,sodium saccharin as template molecule, acrylic as functional monomer, N,Nmethylene-bis-acrylamide as crosslinking agent, ammonium persulfate as an initiator.Characterize the imprinted polymer by transmission electron microscopy, scanning electron microscopy, infrared spectroscopy and thermogravimetric analyzer.In the second part, adsorption kinetics first-order reaction model, adsorption kinetics second-order reaction model and Weber-Morris model are fitted, it shows that:adsorption kinetics second-order reaction model dominates in the three models, and is the rate-limiting step of the adsorption process. The whole process is achieved by electronically shared or electron transfer between adsorbent and adsorbate, is a chemical adsorption process. By fitting Freundlich and Langmuir models of thermodynamics, it shows that: Langmuir model has better fit to saccharin sodium molecular imprinted polymers. This adsorption is a monomolecular layer adsorption. And the structure of polymers is uniform. Through research the adsorption specific of polymer, it shows that:saccharin sodium molecularly imprinted polymers have good specificity to saccharin sodium, almost no absorption of its structural analogs. The maximum adsorption capacity is 8.965mg/g and the imprinting factor is 2.16. Through reusability research, it shows that: the polymer is reused five times, the recovery still remains above 80%.In the third part, saccharin sodium molecularly imprinted polymer will be made a solid phase extraction column as filler material. Its loading and elution conditions were optimized. It shows that: when the flow rate of the sample solution is 0.05 m L/min, the sample will be retained in solid phase extraction column at the greatest degree. When the elution is methanol: acetic acid(v/v=9:1) and the amount of it is 5m L, the best effect will achieve. Then the HPLC detection conditions are optimized, it shows that: when ammonium acetate(0.02mol/L): methanol=95:5 as mobile phase, the flow rate is0.8m L/min, the purpose to detect rapidly can be achieved. Finally, we use the above methods to test peaches canned, sweet sauce and grape juice in actual samples. The recovery of three samples is between 84%-118%, followed by the limit of detection are0.05 μg/g, 0.08 μg/g and 0.08 μg/g, the limit of quantitation are 0.2 μg/g, 0.3 μg/g and0.3 μg/g, it shows that: the method we have created can be applied to the detection of sodium saccharin in real samples.