Papers by Keyword: Molecularly Imprinted Polymer

Abstract: The evaluation of chitosan and resveratrol interactions has been conducted using density functional theory (DFT) to model a slow-release system of the active ingredient resveratrol from the chitosan matrix. The geometry optimization method for modeling was selected using the DFT/B3LYP method with various basis sets. Molecularly imprinted chitosan (MIC) complex models with resveratrol were created in two different configurations. All models were optimized using selected computational methods. The optimized complex models were used to calculate interaction energies and analyze the non-covalent interactions between the MIC cavity and resveratrol. The MIC-resveratrol complex models formed relatively stable supramolecular complexes with a relatively low interaction energy of - 199 kJ/mol for omplex model namely B1 and formed four hydrogen bonds with bond lengths around 1.79-1.91 Å.

Abstract: Molecularly Imprinted Polymer-Oleic Acid (MIPOA) and Molecularly Imprinted Polymer-Palmitic Acid (MIPPA) were synthesized using oleic acid and palmitic acid as the templates; acetonitrile as the porogenic solvent; and allylthiourea as the monomer; and EDGMA as a cross-linker via bulk polymerization. The non-imprinted polymers (NIP) as a control were prepared with the same procedure, but with the absence of template molecule. The synthesized MIPs and NIP were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and the results showed the narrowing of –OH peak which shows that crosslinking has occurred. Field Emission Scanning Electron Microscope-Energy Dispersive X-Ray (FESEM-EDX) was used to analyze the composition of in both MIPs and NIP. The results yielded a composition of C, O, and S. This analysis corresponds to the composition of oleic acid and sulfuric acid as both templates contain -COOH group. These results suggested that the molecularly imprinted polymers can be employed as a potential adsorbent for the removal of oleic acid and palmitic acid from palm fatty acid distillate (PFAD) waste.

Abstract: Palm Fatty Acid Distillate (PFAD) consists of more than 80% of free fatty acids, primarily palmitic acid and oleic acid, which can be esterified and added to the biofuel and oleo-chemical industries as feedstock. Oleic Acid is also known as cis-9-octadecenoic acid has the chemical formula C₁₈H₃₄O₂ or (CH₃(CH₂)₇CHCH(CH₂)₇COOH). There have been numerous studies that demonstrate the nutritional value of oleic acid. The objectives of this research were to simulate the mechanism reaction design for Molecularly Imprinted Polymer (MIP) synthesis and to predict the bonding formed after synthesis by comparing the monomers and template. The mechanism and complexes formed were drawn according to the theoretical mechanism of MIP. The chemicals involved were allylthiourea as the monomer, oleic acid as the template, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, 2,2-azobisisobutyronitrile (AIBN) as the initiator, and acetonitrile as porogenic solvent. The monomer, allylthiourea was compared with the other two monomers which are vinylpyridine and acrylamide in MIP synthesis prediction. On average, when the allylthiourea was used as the monomer, the bond length was quite similar for each connection of atoms (1.316 Angstrom). However, when the vinylpyridine and acrylamide were used as the monomers, the length of the bonds was not similar to each other. On top of that, the bond angles prediction for allylthiourea-oleic acid complex agreed with the molecular geometry shape was tetrahedral due to the average angle was 109.5^o. Next, two different templates; oleic acid and palmitic acid; were compared in MIP synthesis prediction. The bond length for oleic acid was on average quite similar to each other (1.316 Angstrom) whereas for palmitic acid as the template the bond length was not similar. The palmitic acid-allylthiourea complex showed the angles reading was not synchronized to each other and quite unstable, unlike the oleic acid-allylthiourea complex. The results agree that oleic acid as the template was the best in this setting parameter for MIP synthesis.

Abstract: In this work, A molecularly imprinted polymers (MIPs) electrochemical sensor based on chitosan (CS) and nickel electrode was constructed, finally used in glucose measurement. The MIPs sensor was prepared through electrodepositing glucose–CS composited film on the electrochemical treated nickel then removing glucose from the film via water elution. The morphology and electrochemical properties of the sensor were characterized via scanning electron microscope (SEM) , cyclic voltammetry (CV), respectively. Amperometric responses of the CS (MIP)-NiO electrode toward glucose was well-proportional to the concentration of the range from 10 μM to 200 μM. The developed sensor obtained the specific recognition to glucose against coexisting interferences such as oxalic acid, uric acid and ascorbic acid.

Abstract: An electrochemical sensor for estradiol was prepared by a molecularly imprinted polymer (MIP) film and its recognition properties for estradiol were investigated. The polypyrrole (PPy) film was prepared by electropolymerizing pyrrole on gold nanoparticles (Au NPs) and graphene (Gs) modified glassy carbon (GC) electrode. The electrochemical response of 17β-Estradiol (17β-E2) at the imprinted PPy-Gs-Au/GC electrode was investigated by cyclic voltammetry. The results indicated that the imprinted PPy-Gs-Au/GC electrode can effectively improve the electrochemical signal of 17β-E2 and eliminate interferences of other interfering substances. The results showed that a wide detection linear range (3.0 × 10^-9 1.0 × 10^-6 mol L^-1) for the determination of 17β-E2 with the low detection limit of 1.0 × 10^-9 mol L^-1 (S/N = 3) was obtained. The proposed sensor exhibited fast balance response time of 10 min, which is propitious to rapid detect 17β-E2 in real samples. The merits of the imprinted electrode suggested an attractive and broadly applicable way for developing the chemical sensor used for the estrogen detection.

Abstract: A new molecularly imprinted polymer, which can be used for selective adsorption of chloramphenicol (CAP) from aqueous solutions, was successfully prepared by precipitation polymerization. The adsorption kinetic curve, adsorption isotherm and selective adsorption were measured by static method. The adsorption kinetics of MIPs for CAP reached the equilibrium at about 11 hours. The maximum adsorption capacity was 43.395 mmol/g, and the MIP has much higher adsorption quantity than NIP. Competitive adsorption studies showed that MIP offers the advantages of selectivity toward CAP compared with NIP in the presence other antibiotics. The results showed that the MIP possessed good specific adsorption capacity and selectivity for CAP.

Abstract: Polystyrene microspheres were prepared by the emulsifier-free polymerization method. Using the polystyrene microspheres as seeds, 2,4-dichlorophenoxyacetic acid as template molecules, the monodispersed molecularly imprinted polymer microspheres (MIPMs) were prepared by a single-step swelling and polymerization method. The monodispersed molecular imprinted polymers with porous structure were characterized by SEM, and UV-visible spectrophotometry. The adsorption performance of MIPMs for 2,4-dichlorophenoxyacetic acid was investigated.

Abstract: Molecular imprinted polymers were synthesized with precipitation polymerization in the present study when Erythromycin was used as template, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linker. The best synthesis solution was ultimately determined when the bonding property of the polymer was studied. The selectivity of imprinted polymer on Erythromycin was also studied. The equilibrium binding experiments showed that the binding site of MIPs was heterogeneous with one binding site. Equilibrium dissociation constant was 0.663mg/ml, maximum apparent adsorption was 91.39mg/g.

Abstract: The synthesis and performance of a molecularly imprinted polymer (MIP) designed to enable the clean-up of the interferences existing in alprazolam (Alpra) drug samples is described. The MIP was synthesized using non-covalent molecularly imprinted method. Nimetazepam (Nimet), which has a similar chemical structure as the major impurities in Alpra drug samples, was used as the dummy template. Methacrylic acid was used as the monomer. Both the affinity and selectivity of the MIP for Nimet and structurally related compounds were examined through batch-rebinding studies. The specific binding amount of Nimet was determined to be 11.4 mg•g-1. The MIP was used as the sorbent in solid phase extraction (MI-SPE) and methanol was used as the washing solvent for the clean-up of Nimet in the Alpra complex samples. The effective clean-up of Nimet was achieved, with a recovery > 90% for Alpra, in the stimulated samples.

Abstract: A kind of sulfanilic acid molecularly imprinted polymer (MIP) was synthesized by reverisible addition fragmentation chain transfer (RAFT) process using (4-cyanopentanoic acid)-4-dithiobenzoate (CTA-2) as chain transfer reagent, methacrylic acid (MAA) as functional monomer and hydrophobic ionic liquids, 1-butyl-3-methylimidazolium hexfluorophosphate ([bmim]PF6), as functional reaction medium. The results showed that the obtained MIPs had regular shape with high affinity to sulfonamides, and when it was empolyed as the adsorbtion sorbent of solid phase extraction for selectively extracted the three kinds of sulfonamides (sulfamerazine, sulfadiazine and sulfamethoxazole) from chicken samples, the interferences of chicken matrix could be eliminated efficiently and the recoveries at three spiked leves were satisfied.