scholarly journals A Molecular Imprinted Polymer as a Flow-Through Optical Sensor for Oxazepam

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Roberta G. Machicote ◽  
Marcela A. Castillo ◽  
Maria E. Pacheco ◽  
Liliana Bruzzone

A flow-through optosensing system for oxazepam recognition with fluorescence detection was performed by means of a molecular imprinted polymer based on its acid hydrolysis product, 2-amino-5-chlorobenzophenone. The synthesis was conducted via a noncovalent imprinting methodology, using methacrylic acid as a functional monomer and ethylene glycol dimethacrylate as a cross-linking agent. Hydrolysis (types and concentration of acids), polymer retention capacity, binding properties, and elution (selectivity and reversibility) conditions were optimized. The selected molecular imprinted polymer had a molar ratio composition of 1 : 6 : 45 (template : functional monomer : cross-linker). The proposed method was applied to the determination of oxazepam in a pharmaceutical formulation. External standard calibration, standard additions calibration, and Youden’s calibration were carried out in order to evaluate constant and proportional errors due to the matrix. The developed metabolite-based recognition system for benzodiazepines is an innovative procedure that could be followed in routine and quality control assays.

2018 ◽  
Vol 16 (1) ◽  
pp. 12 ◽  
Author(s):  
Saeful Amin ◽  
Sophi Damayanti ◽  
Slamet Ibrahim

The research related to the interaction study, synthesis and characterization of molecular imprinted polymer using dimethylamylamine (DMAA) as the template molecule and the functional monomer methacrylate acid has been conducted. Molecular Imprinted Polymer (MIP) is a separation method made by the molecule template in the polymer matrix followed by removing the template molecule by washing for giving the permanent framework groove. The MIP was made by mixing the DMAA as the template molecule, with the methacrylate acid as the functional monomer, and the ethylene glycol dimethacrylate (EGDMA) as the crosslinker with the ratio 1:6:20. Porogen solvents used were the chloroform and the initiator azobisisobutyronitrile (AIBN). The crystal MIP and the NIP without the DMAA were characterized using Infrared Spectrophotometer (FTIR), and the result showed that there have been differences among the MIP, the NIP and the MIP after being extracted. The characterization using Scanning Electron Microscope (SEM) showed that the NIP as the comparison having flat morphology, while the MIP having irregular morphology and less pores. Then the MIP after being extracted has irregular, rough morphology and a lot of pores. The result reveals the interaction between the DMAA and the methacrylate acid that is the hydrogen bonded with the Gibbs free energy obtained is -5.434 j/mol. The imprinting factor of 2,353 is obtained. The highest desorption descending capacity is chloroform with the MIP 738% better. For the MIP and NIP methanol, it is found that the MIP is 123% better. Then the MIP which is desorbed by the chloroform is better 602% than the MIP resorbed by the methanol, and the ethyl acetate cannot desorb the DMAA.


Author(s):  
Sophi Damayanti ◽  
Untung Gunawan ◽  
Slamet Ibrahim

Background: The use of nitrofurantoin and other nitrofuran antibiotics in food which produced from animals is prohibited by European Union because of potentially carcinogenic and mutagenic. Various methods for analysis of residues of nitrofurantoin has been developed, but because of the interference of the matrix, it is necessary to separate the matrix therefore, the matrix effect will not interfere the analysis. Nowadays, molecular imprinted polymer (MIP) is a well-developed tool in the analytical field, mainly for separating substances in relatively complex matrices.Objective: The purpose of this study is to obtain MISPE that is selective for the separation of nitrofurantoin residues in chicken eggs.Methods: Analytical methods development of nitrofurantoin were optimization of HPLC system and validation of analytical methods performed to obtain the suitable system for nitrofurantoin detection. In silico study used for MIP design by observing the difference Gibbs free energy using Gaussview 5.08 software with Density Functional Theory (DFT) methods using 6-311G as basis set. MIP synthesis was done using bulk method use nitrofurantoin as template, acrylamide as functional monomer, ethyleneglycoldimethacrylate (EGDMA) as crosslinker, and azobisisobutyronitrile (AIBN) as an initiator reaction inside dimethylformamide (DMF) as solvent. Non imprinted polymer (NIP) was synthesized as comparison. MIP and NIP which has been synthesized was inserted into SPE cartridge and characterized using Infrared spectroscopy and HPLC.Result: MISPE that has been synthesized was characterized and compared to non-imprinted polymer solid phase extraction (NISPE) and marketed Solid Phase Extraction (SPE) C18. Sensitivity of MIP, NIP, and SPE C-18 to nitrofurantoin was 84.54 %, 37.73 %, and 33.95 % respectively, based on recovery of nitrofurantoin.Conclusion: Based on the result it was obtained MISPE has high selectivity toward nitrofurantoin compared to NISPE and either marketed SPE.  


2000 ◽  
Vol 405 (1-2) ◽  
pp. 67-76 ◽  
Author(s):  
Jorge Luis Suárez-Rodrı́guez ◽  
Marta Elena Dı́az-Garcı́a

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1389 ◽  
Author(s):  
Yu-Jie Huang ◽  
Rui Chang ◽  
Qiu-Jin Zhu

Spermidine is a functional ingredient that can extend the lifespan of many foods and indicate meat safety. However, its synthesis and enrichment is expensive and complex. To develop an effective separation material that can offer highly selective recognition of spermidine, we first applied non-covalent molecular imprinting technology using methacrylic acid as a functional monomer, azobisisobutyronitrile as an initiator, and ethylene glycol dimethacrylate as a cross-linker. The adsorption properties of the polymers were analyzed using the Scatchard equation, the Lagergren kinetic equation, and the static distribution coefficient. The optimal polymerization molar ratio of the template molecule spermidine to the functional monomer was 1:4, the maximum adsorption amount was 97.75 μmol/g, and the adsorption equilibrium time was 300 min. The selective experiment showed that the interfering substances tyramine and histamine had selectivity factor α values of 2.01 and 1.78, respectively, indicating that the prepared polymer had good spermidine recognition ability. The density function theory calculations showed that the hydrogen bond strength, steric effect, and product energy caused adsorption and separation differences among the different imprinted polymer complexes.


Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 855
Author(s):  
Ahmed Amine Azzaz ◽  
Salah Jellali ◽  
Nasser Ben Harharah Hamed ◽  
Atef El Jery ◽  
Lotfi Khezami ◽  
...  

In the present study, methylene blue (MB) removal from aqueous solutions via the photocatalytic process using TiO2 as a catalyst in the presence of external ultra-violet light (UV) was investigated. The results of adsorption in the absence of UV radiation showed that adsorption reached an equilibrium state at 60 min. The experimental kinetic data were found to be well fitted by the pseudo-second-order model. Furthermore, the isotherm study suggested that dye uptake by TiO2 is a chemisorption process with a maximum retention capacity of 34.0 mg/g. The photodegradation of MB was then assessed under various experimental conditions. The related data showed that dye mineralization decreased when dye concentrations were increased and was favored at high pH values and low salt concentrations. The simultaneous presence of organic and inorganic pollution (Zinc) was also evaluated. The effect of the molar ratio Zn2+/MB+ in the solution at different pH values and NaCl concentrations was also monitored. The corresponding experimental results showed that at low values of Zn2+ in the solution (30 mg/L), the kinetic of the MB removal became faster until reaching an optimum at Zn2+/MB+ concentrations of 60/60 mg/L; it then slowed down for higher concentrations. The solutions’ carbon contents were measured during the degradation process and showed total mineralization after about 5 h for the optimal Zn2+/MB+ condition.


2021 ◽  
Vol 11 (12) ◽  
pp. 5370
Author(s):  
Ana M. Borreguero ◽  
Irene Izarra ◽  
Ignacio Garrido ◽  
Patrycja J. Trzebiatowska ◽  
Janusz Datta ◽  
...  

Polyurethane (PU) is one of the principal polymers in the global plastic market thanks to its versatility and continuous improvement. In this work, PU elastomeric materials having thermoregulating properties through the incorporation of microcapsules (mSD-(LDPE·EVA-RT27)) from low-density polyethylene and vinyl acetate containing paraffin®RT27 as PCM were produced. Elastomers were synthesized while varying the molar ratio [NCO]/[OH] between 1.05 and 1.1 and the microcapsule (MC) content from 0.0 to 20.0 wt.%. The successful synthesis of the PUs was confirmed by IR analyses. All the synthesized elastomers presented a structure formed by a net of spherical microparticles and with a minimum particle size for those with 10 wt.% MC. The density and tensile strength decreased with the MC content, probably due to worse distribution into the matrix. Elastomer E-1.05 exhibited better structural and stability properties for MC contents up to 15 wt.%, whereas E-1.1, containing 20 wt.% MC, revealed mechanical and thermal synergy effects, demonstrating good structural stability and the largest latent heat. Hence, elastomers having a large latent heat (8.7 J/g) can be produced by using a molar ratio [NCO]/[OH] of 1.1 and containing 20 wt.% mSD-(LDPE·EVA-RT27).


2021 ◽  
Author(s):  
Yue Shi ◽  
Kishore Mohanty ◽  
Manmath Panda

Abstract Oil-wetness and heterogeneity (i.e., existence of low and high permeability regions) are two main factors that result in low oil recovery by waterflood in carbonate reservoirs. The injected water is likely to flow through high permeability regions and bypass the oil in low permeability matrix. In this study, systematic coreflood tests were carried out in both "homogeneous" cores and "heterogeneous" cores. The heterogeneous coreflood test was proposed to model the heterogeneity of carbonate reservoirs, bypassing in low-permeability matrix during waterfloods, and dynamic imbibition of surfactant into the low-permeability matrix. The results of homogeneous coreflood tests showed that both secondary-waterflood and secondary-surfactant flood can achieve high oil recovery (>50%) from relatively homogenous cores. A shut-in phase after the surfactant injection resulted in an additional oil recovery, which suggests enough time should be allowed while using surfactants for wettability alteration. The core with a higher extent of heterogeneity produced lower oil recovery to waterflood in the coreflood tests. Final oil recovery from the matrix depends on matrix permeability as well as the rock heterogeneity. The results of heterogeneous coreflood tests showed that a slow surfactant injection (dynamic imbibition) can significantly improve the oil recovery if the oil-wet reservoir is not well-swept.


2015 ◽  
Vol 203 ◽  
pp. 32-40 ◽  
Author(s):  
M. Sánchez-Polo ◽  
I. Velo-Gala ◽  
Jesús J. López-Peñalver ◽  
J. Rivera-Utrilla

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