Electrochemical Sensor Fabricated By Molecular Imprinting Polymer Membrane Based On Modified Rosin As Cross-linker

Molecularly imprinted polymers (MIPs) have increasingly attracted considerable attention by the researchers, because it has outstanding advantages of resistant high temperature and pressure, robustness in acidic or basic reagents, mimic molecular recognition by natural drugs. Besides, MIPs have the characters with predetermination, specific recognition and practicability, which provide synthetic MIPs membrane with high selectivity and stability. Though the main applications of MIPs membrane continue to be in the separation field, electrochemical sensors have been considerably studied as recognition component due to its advantages such as simple and convenient preparation, high sensitivity, wide linear range, detection limit low and at low lost.Cross-linker is one material which contact with the linear molecules and synthetic the MIPs. It can not only improve the polymers’thermostability, selectivity and mechanical strength, but also reduce the polymers’swelling effect in different solvent. In this paper, four kinds of natural drugs molecularly imprinted electrochemical sensors were synthesized successfully with ethylene glycol maleic rosinate acrylate as cross-linker. The main contents are summarized as follows:1. Using methyl acrylic acid as functional monomer, caffeine as template, ethylene glycol maleic rosinate acrylate as cross-linker, a novel molecularly imprinted membrane (MIM) on a glassy carbon electrode was prepared by situ heating-initiated merization method for the detection of caffeine. The imprinting effect, performance and selective response were studied by the electrochemical methods in the solution of potassium ferricyanide. The sensor showed high selectivity and good sensitivity towards the target caffeine and it gave a linear correlation to caffeine concentration over a range from3.00×10-6to2.73×10-3mol·L-1with a detection limit of1.12×10-7mol·L-1(S/N=3). The sensor had been applied to the analysis of caffeine in coca-cola samples with recovery ranging from95.0%to103%.2. Using acrylic acid as functional monomer, theophylline as template, ethylene glycol maleic rosinate acrylate as cross-linker, a novel molecularly imprinted membrane (MIM) on a glassy carbon electrode was prepared by situ heating-initiated merization method for the detection of theophylline. The imprinting effect, performance and selective response were studied by the electrochemical methods in the solution of potassium ferricyanide. The sensor showed high selectivity and good sensitivity towards the target theophylline and it gave a linear correlation to theophylline concentration over a range from2.00×10-7to3.45×10-4mol·L-1with a detection limit of1.0×10-7mol·L-1(S/N=3). The sensor had been applied to the analysis of theophylline in theophylline sustained release tablets samples with recovery ranging from95.6%to104%.3. Using acrylamide as functional monomer, daidzein as template, ethylene glycol maleic rosinate acrylate as cross-linker, molecularly imprinted membrane (MIM) on a glassy carbon electrode was prepared by electropoly merization method for the determination of daidzein. The imprinting effect, performance and selective response were studied by the electrochemical methods. A method for determining daidzein was established with daidzein was worked as the probe between the electrode and base solution of Britton-Robinson. The sensor showed high selectivity and good sensitivity towards the target daidzein and it gave a linear correlation to daidzein concentration over a range from1.00×10-8to2.97×10-4mol-L-1with a detection limit of7.00×10-9mol·L-1(S/N=3). The sensor had been applied to the analysis of daidzein in soybean isoflavone capsule samples with recovery ranging from94.5%to104%. 4. Using acrylamide as functional monomer, puerarin as template, ethylene glycol maleic rosinate acrylate as cross-linker, molecularly imprinted membrane (MIM) on a glassy carbon electrode was prepared by electropoly merization method for the determination of puerarin. The imprinting effect, performance and selective response were studied by the electrochemical methods. A method for determining puerarin was established with puerarin was worked as the probe between the electrode and base solution of NH4Cl-KCl-NH3·H2O. The sensor showed high selectivity and good sensitivity towards the target puerarin and it gave a linear correlation to puerarin concentration over a range from6.00×10-8to1.60×10-3mol·L-1with a detection limit of2.00×10-8mol·L-1(S/N=3). The sensor had been applied to the analysis of puerarin in puerarin injection and papaya&pueraria root tablet samples with recovery ranging from97.7%to107%.