Non-covalent Imprinting Approach Research Articles

Development of a molecularly imprinted polymeric membrane for determination of macrolide antibiotics from cow milk

A molecular imprinted membrane (MIM) was prepared for the selective binding of macrolide antibiotics by UV-initiated non-covalent imprinting approach. The membrane was modified by a UV-photographting technique in the presence of molecule templates of erythromycin (ERY) and spiramycin (SPI) with methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The nanofunctionalized MIM obtained was characterized by a morphological study using scanning electron microscopy (SEM), as well as by a study of its adsorption capacity by online solid phase extraction (SPE) procedure. Variables affecting the MIM-SPE method were optimized to maximize the extraction of macrolide antibiotics of interest and a high-performance liquid chromatography (HPLC) method was used for the analysis. Good linearity and precision were obtained for ERY and SPI, with average recoveries up to 86.14% and 34.73%, respectively, with a relative standard deviation (RSD) lower than 6%. In addition, selectivity was studied for other macrolides with similar structure to the templates, such as roxithromycin (ROX), josamycin (JOS), ivermectin (IVER) and tylosin (TYL). The proposed MIM-SPE-HPLC methodology was effectively applied to ERY and SPI determination in commercial doped semi-skimmed cow's milk samples.

MOLECULARLY IMPRINTED POLYMER FOR THE BINDING AND RECOGNITION OF BASIC BLUE 41 DYE

This study reports a novel imprinted molecular poly(ethylene terephatalate) (MIPBB41) for the binding and selective recognition of an azoic dye (basic blue 41) by a non-covalent imprinting approach. Basic blue 41 (BB41) was chosen as the template molecule, acrylic acid-grafted polyethylene terephthalate (PET-g-AA), and N,N’-methylene-bis-acrylamide (MBA) were used as the functional polymer and crosslinking reagent respectively. To determine the binding capacity of MIPBB41, several adsorption studies were performed. The adsorption isotherm was described by the Langmuir model, and the maximum adsorption capacity of MIPBB41 toward basic blue 41 reached 144.8 mg g-1in water at pH 6.2. The fabricated MIP showed good recognition properties. In a further experiment, the adsorption capacity of the MIP was compared to the non-imprinted polymer (NMIP), and a recognition coefficient of 3.14 was obtained.

Molecularly Imprinted Solid-Phase Extraction Sorbents for the Selective Extraction of Drugs from Human Urine.

Development of molecularly imprinted solid-phase extraction (MISPE) sorbents for the removal of drugs from human urine is described. MISPE sorbents are synthesized through free radical polymerization mechanism and non-covalent imprinting approach. After the completion of the polymerization, bulk polymer is ground using an analytical mill and then wet-sieved. Later on, MISPE sorbent has been dry-packed into solid-phase extraction cartridges after the extraction of template drug molecule. Eluates from the cartridges are analyzed using a spectrophotometer or spectrofluorimeter for the determination of target analyte by referring to the calibration curves.

Synthesis and characterization of α-mangostin imprinted polymers and its application for solid phase extraction

α-mangostin imprinted polymers have been synthesized by a non-covalent imprinting approach with α-mangostin as a template molecule. The α-mangostin molecularly imprinted polymers (MIPs) prepared by radical polymerization using methacrylic acid, ethlylene glycol dimethacrylate, benzoyl peroxide, and acetonitrile, as a monomer, crosslinker, initiator, and porogen, respectively. The template was removed by using methanol:acetic acid 90:10 (v/v). The physical characteristics of the polymers were investigated by Fourier Transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The rebinding studies were carried out by batch methods. The results exhibited that the MIPs was able to adsorb the α-mangostin at pH 2 and the contact time of 180 min. The kinetic adsorption data of α-mangostin performed the pseudo-second order model and followed the Langmuir isotherm model with the adsorption capacity of 16.19 mg.g-1. MIPs applied as a sorbent material in solid-phase extraction, namely molecularly imprinted solid-phase extraction (MISPE) and it shows the ability for enrichment and clean-up of α-mangostin from the complex matrix in medicinal herbal product and crude extract of mangosteen (Garcinia mangostana L.) pericarp. Both samples, respectively, which were spiked with α-mangostin gives recovery more than 90% after through by MISPE in all concentration ranges.

Efficient Recognition and Determination of Carbamazepine and Oxcarbazepine in Aqueous and Biological Samples by Molecularly Imprinted Polymers

A molecularly imprinted polymer (MIP) of carbamazepine (CBZ) was synthesized so as to facilitate the selective extraction of CBZ from aqueous and bio-samples by using a non-covalent imprinting approach. Synthesized materials were characterized with Fourier-transform infrared spectroscopy and scanning electron microscopy studies. The imprinted polymer was evaluated and applied as a sorbent for solid-phase extraction (SPE) coupled with HPLC-UV to detect CBZ and its metabolite oxcarbazepine (OXC). The optimal conditions for molecularly imprinted SPE (MISPE) consist of the cartridge conditioning using methanol followed by triply distilled water, loading the aqueous sample and elution by methanol-acetic acid (9 : 1, v/v). The selectivity and sensitivity for pre-concentration and separation of the target analytes were studied in details, in order to build a simple and sensitive method which can act as a potential analytical strategy to monitor CBZ and OXC in the environmental and biological samples. The developed method exhibited a wide linear range (1–500 μg/L), good linearity (R2 > 0.990), and relative standard deviation <3%. The molecular recognition properties of the MIP gave rise to good recoveries for CBZ (87–98%) and OXC (72–78%) when spiked aqueous and bio-samples were percolated through the MISPE procedure. The limit of detection for CBZ and OXC were 0.488 and 0.515 μg/L, respectively. Moreover, each MISPE cartridge, when investigated for reusability test, displayed excellent recoveries for CBZ (98–94%) with enhanced reusability (10 cycles).

CdS quantum dots-based immunoassay combined with particle imprinted polymer technology and laser ablation ICP-MS as a versatile tool for protein detection

For the first time, the combination of molecularly imprinted polymer (MIP) technology with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is presented with focus on an optimization of the LA-ICP-MS parameters such as laser beam diameter, laser beam fluence, and scan speed using CdS quantum dots (QDs) as a template and dopamine as a functional monomer. A non-covalent imprinting approach was employed in this study due to the simplicity of preparation. Simple oxidative polymerization of the dopamine that creates the self-assembly monolayer seems to be an ideal choice. The QDs prepared by UV light irradiation synthesis were stabilized by using mercaptosuccinic acid. Formation of a complex of QD-antibody and QD-antibody-antigen was verified by using capillary electrophoresis with laser-induced fluorescence detection. QDs and antibody were connected together via an affinity peptide linker. LA-ICP-MS was employed as a proof-of-concept for detection method of two types of immunoassay: 1) antigen extracted from the sample by MIP and subsequently overlaid/immunoreacted by QD-labelled antibodies, 2) complex of antigen, antibody, and QD formed in the sample and subsequently extracted by MIP. The first approach provided higher sensitivity (MIP/NIP), however, the second demonstrated higher selectivity. A mixture of proteins with size in range 10–250 kDa was used as a model sample to demonstrate the capability of both approaches for detection of IgG in a complex sample.

Site-specific post-imprinting modification of molecularly imprinted polymer nanocavities with a modifiable functional monomer for prostate cancer biomarker recognition

ABSTRACT Recognition of glycans of glycoproteins using biotic materials such as antibodies is challenging due to lack of antigenicity. Polymeric materials suitable for the molecular recognition of glycoproteins have attracted considerable attention. In this study, we aimed to develop abiotic molecular materials for the recognition of prostate-specific antigen (PSA), a known biomarker for prostate cancer. We used a non-covalent bonding-based molecular imprinting technique to introduce post-imprinting poly(ethylene glycol)-based capping agent into a low-affinity recognition cavity. Details of the binding properties of these groups were investigated to optimize their affinity and selectivity for PSA. Molecularly imprinted polymers (MIPs) were prepared using a bottom-up approach based on surface-initiated atom transfer radical polymerization from a PSA-conjugated sensor chip with a functional monomer-bearing carboxy and secondary amine groups as interaction and post-imprinting modification (PIM) sites, respectively. PSA was orientationally conjugated on the sensor chip through diesters between the immobilized 3-fluorophenyl boronic acid and the cis-diol groups of PSA glucans. Treatment with the capping agent selectively inactivated low-affinity recognition cavities while protecting high-affinity cavities with the addition of a low concentration of PSA as a dynamic protection agent. The MIP thickness is critical in the present molecular imprinting, as a value of less than 5 nm can enable high selectivity. We believe that the proposed strategy based on a non-covalent molecular imprinting approach combined with a PIM-based capping treatment provides a novel method for the development of highly sensitive and selective glycoprotein recognition materials for use in biomarker sensing.

Preparation of molecularly imprinted PDMS elastomer for selective detection of folic acid in orange juice

Herein, it is reported an effective method to prepare novel molecularly imprinted polymers (MIP) on poly(dimethylsiloxane) (PDMS) elastomer via a combination of non-covalent imprinting approach and surface initiated reversible addition fragmentation chain transfer (SI-RAFT) polymerization for sensitive and selective detection of folic acid (FA). For this purpose, 2-(2-Methoxyethoxy) ethyl methacrylate (MEOMA), ethylene glycol dimethacrylate (EGDMA), azobisisobutyronitrile (AIBN), FA and dimethylsulfoxide (DMSO) were used as functional monomer, cross-linker, initiator, template molecule, and porogen, respectively. The adsorption behavior followed the Scatchard equation between FA and PDMS-MIP with a saturation adsorption capacity of 4.51 mg/g and pseudo-second-order kinetics with 60 min equilibrium adsorption time. Furthermore, PDMS-MIP elastomer was successfully applied for selective extraction and detection of FA from orange juice with sufficient recovery (95.5–100.5%) and relative standard deviation less than 7.0%. The limit of detection (LOD) for FA was found to be 0.0031 µg/mL with a linear range between 0.01 and 100 µg/mL and a correlation coefficient of 0.9997. Results showed the proposed method could easily, efficiently and selectively extracted FA from complex media. Note that this novel proposed method will open a new way to detect any selected molecules such as pesticide, protein, drug, etc. using molecularly imprinted PDMS elastomer materials.

Application of Molecular Imprinted Polymers for Selective Solid Phase Extraction of Bisphenol A

Abstract Selective molecularly imprinted polymers (MIPs) with bisphenol A as template were synthesized using the non-covalent imprinting approach. MIPs were prepared using thermally initiated polymerization with 1,1’-azobis(cyclohexanecarbonitryle) (ACHN) as initiator and ethylene glycol dimethacrylate (EDMA) as a cross-linking agent. The tested functional monomers included methacrylic acid, acrylamide, and 4-vinylpyridine. The selectivity of the BPA-MIP for the solid phase extraction of bisphenol A was tested in samples containing other related alkylphenols. The polymers prepared in acetonitrile using methacrylic acid or acrylamide as monomer showed the highest selectivity towards target analyte (the selectivity ratio 8:1, respectively for MIP and NIP). The proposed procedure has been proven to be an effective for selective extraction of bisphenol A in aqueous samples (recoveries over 85%) enabling detection and quantification limits of 25 and 70 μg/dm3, respectively based on 10 cm3 of sample volume, with relative standard deviations (RSD) lower than 6%. The obtained molecularly imprinted material showed interesting properties for selective extraction and preconcentration of studied analyte from large volumes of aqueous samples without any problems of cartridge clogging.

Multiresidue analysis of cephalosporin antibiotics in bovine milk based on molecularly imprinted polymer extraction followed by liquid chromatography-tandem mass spectrometry

This work reports the preparation of molecularly imprinted polymers (MIPs) selective to cephalosporin (CF) antibiotics, and their application as molecularly imprinted solid-phase extraction (MISPE) sorbents for the determination of these antimicrobials in milk samples. Several functional monomers and cross-linkers have been screened to select the best combination that provides high selectivity for the simultaneous multiresidue extraction of cefthiofur (THIO), cefazolin (AZO), cefquinome (QUI), cephapirin (API), cephalexin (ALE) and cephalonium (ALO) from the samples. The novel MIPs were prepared by a non-covalent imprinting approach in the form of spherical microparticles using the synthetic surrogate molecule sodium 7-(2-biphenylylcarboxamido)-3-methyl-3-cepheme-4-carboxylate, N-3,5-bis(trifluoromethyl)phenyl-N′-4-vinylphenyl urea (VPU) as functional monomer, and divinylbenzene (DVB) as crosslinking agent in a 1:2:20 molar ratio. The optimized MISPE method allowed the extraction of the target antimicrobials from raw cow milk samples using a selective washing with 5mL methanol/2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES) buffer (0.1M, pH 7.5) (2:98, v/v) to remove the non-specifically retained compounds, followed by elution with 1mL of trifluoroacetic acid (TFA) in methanol (0.1:99.9, v/v). The extracts have been analysed by UHPLC–MS/MS and the analytical method has been validated according to EU guideline 2002/657/EC. The limits of quantification (S/N=10) were in the 1.7–12.5μgkg−1 range, well below the maximum residue limits (MRLs) currently established for the quantified cephalosporins in milk samples. The developed MIP allows mutiresidual determination of the six cephalosporin antibiotics mentioned above, significantly broadening the application to food analysis of MISPE methods.

Binding characteristics of molecularly imprinted polymers based on fungicides in hydroalcoholic media.

An iprodione-imprinted polymer was prepared by copolymerization of methacrylamide and ethylene glycol dimethacrylate using a noncovalent imprinting approach. Methacrylamide was chosen using molecular dynamics simulations. To concentrate iprodione from hydro-alcoholic solutions, batch sorption of iprodione on the imprinted polymer were conducted. The equilibrium time for iprodione sorption is 20 min, and the corresponding kinetic mechanism follows the pseudo-second order indicating a strong interaction between iprodione and the imprinted polymer. Langmuir, Freundlich, and Dubinin-Radushkevich models were used to fit the isotherm of iprodione sorption. The imprinted polymer was found to be more efficient than the nonimprinted polymer for the uptake of iprodione, as revealed by its higher adsorption energy, affinity, and capacity. Finally, a selectivity study was conducted on the imprinted and the nonimprinted polymers to sorb three fungicides. It shows that the imprinted polymer could be used as a preconcentration phase in a multiresidue analysis of fungicides in hydroalcoholic medium.

Preconcentration of indapamide from human urine using molecularly imprinted solid-phase extraction.

A simple, sensitive, and selective molecularly imprinted solid-phase extraction and spectrophotometric method has been developed for the clean-up and preconcentration of indapamide from human urine. Molecularly imprinted polymers were prepared by a non-covalent imprinting approach using indapamide as a template molecule, 2-(trifluoromethyl) acrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, N,N-azobisisobutyronitrile as a thermal initiator and acetonitrile as a porogenic solvent. A non-imprinted polymer was also prepared in the same way, but in the absence of template. Molecularly imprinted polymer and non-imprinted polymer sorbents were dry-packed into solid-phase extraction cartridges. Eluates from cartridges were analyzed using a spectrophotometer for the determination of indapamide by referring to the calibration curve in the range 0.14-1.50 μg/mL. Preconcentration factor, limit of detection, and limit of quantification were 16.30, 0.025 μg/mL, and 0.075 μg/mL, respectively. A relatively high imprinting factor (9.3) was also achieved and recovery values for the indapamide spiked into human urine were in the range of 80.1-81.2%. In addition, relatively low within-day (0.17-0.42%) and between-day (1.1-1.4%) precision values were obtained as well. The proposed molecularly imprinted solid-phase extraction and spectrophotometric method was successfully applied to selective extraction, preconcentration, and determination of indapamide from human urine samples.

Development of a molecularly imprinted solid-phase extraction sorbent for the selective extraction of telmisartan from human urine.

A novel molecularly imprinted solid-phase extraction with spectrofluorimetry method has been developed for the selective extraction of telmisartan from human urine. Molecularly imprinted polymers were prepared by a noncovalent imprinting approach through UV-radical polymerization using telmisartan as a template molecule, 2-dimethylamino ethyl methacrylate as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, N,N-azobisisobutyronitrile as an initiator, chloroform as a porogen. Molecularly imprinted polymers and nonimprinted control polymer sorbents were dry-packed into solid-phase extraction cartridges, and eluates from cartridges were analyzed using a spectrofluorimeter. Limit of detection and limit of quantitation values were 11.0 and 36.0 ng/mL, respectively. A very high imprinting factor (16.1) was achieved and recovery values for the telmisartan spiked in human urine were in the range of 76.1-79.1%. In addition, relatively low within-day (0.14-1.6%) and between-day (0.11-1.31%) precision values were obtained. Valsartan was used to evaluate the selectivity of sorbent as well. As a result, a sensitive, selective, and simple molecularly imprinted solid-phase extraction with spectrofluorimetry method has been developed and successfully applied to the direct determination telmisartan in human urine.

Characterization of particle morphology of biochanin A molecularly imprinted polymers and their properties as a potential sorbent for solid-phase extraction.

Molecularly imprinted polymers (MIPs) with biochanin A as a template were obtained using a bulk polymerization with non-covalent imprinting approach. The polymers were prepared in acetonitrile as porogen, using ethylene glycol dimethacrylate (EDMA) as cross-linking agent. The synthesis, with an application of 1',1'-azobis(cyclohexanecarbonitrile) (ACHN) as an initiator, has been performed thermally. During the synthesis process the effect of different functional monomers such as methacrylic acid (MAA), acrylamide (AA) and 4-vinylpyridine (4-VP) was investigated. The application of nitrogen sorption porosimetry, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) permitted the characterization and evaluation of synthesized polymers. The adsorption capacity of obtained MIPs was checked by using the binding testing. All synthesized polymers were evaluated as solid-phase extraction (SPE) sorbents for isolation and preconcentration of biochanin A and its analogues, daidzein and genistein. The MIPs exhibited higher affinity for biochanin A over competitive compounds.

Molecularly imprinted polymers for cleanup and selective extraction of curcuminoids in medicinal herbal extracts.

This paper describes the synthesis of novel molecularly imprinted polymers (MIPs), prepared by a noncovalent imprinting approach, for cleanup and preconcentration of curcumin (CUR) and bisdemethoxycurcumin (BDMC) from medicinal herbal extracts and further analysis by high-performance liquid chromatography with fluorescence detection (HPLC-FLD). Two molecular mimics, a mixture of reduced BDMCs and 4-(4-hydroxyphenyl)-2-butanone (HPB), have been synthesized and applied as templates for MIP synthesis. The polymers were prepared using N-(2-aminoethyl) methacrylamide (EAMA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as the cross-linker (in a 1:5 molar ratio), and a mixture of acetonitrile/dimethylsulfoxide (90%, v/v) as porogen. MIPs prepared using a mixture of reduced BDMCs as template showed higher selectivity for CUR and BDMC than those obtained with HPB, with imprinting factors of 3.5 and 2.7 for CUR and BDMC, respectively, using H2O/acetonitrile (65:35, v/v) as mobile phase. The adsorption isotherms for CUR in the MIP and the nonimprinted polymer (NIP) were fitted to the Freundlich isotherm model, and the calculated average binding affinities for CUR were (17 ± 2) and (8 ± 1) mM(-1) for the MIP and the NIP, respectively. The polymers were packed into solid-phase extraction (SPE) cartridges, and the optimized molecularly imprinted solid-phase extraction (MISPE-HPLC) with fluorescence detection (FLD) method allowed the extraction of both curcuminoids from aqueous samples (50 mM NH4Ac, pH 8.8) followed by a selective washing with acetonitrile/NH4Ac, 50 mM at pH 8.8 (30:70%, v/v), and elution with 3 × 1 mL of MeOH. Good recoveries and precision ranging between 87 and 92%, with relative standard deviation (RSD) of <5.3% (n = 3), were obtained after the preconcentration of 10-mL solutions containing both CUR and BDMC at concentrations in the range of 0-500 μg L(-1). The optimized method has been applied to the analysis of both curcuminoids in medicinal herbal extracts.

Preparation of composite‐imprinted alumina membrane for effective separation of p‐hydroxybenzonic acid from its isomer using Box–Behnken design–based statistical modeling

ABSTRACTHighly selective composite imprinted membrane for p‐hydroxybenzonic acid (p‐HB) was prepared by using semicovalent imprinting technique. A thermally reversible covalent bond was used to link p‐HB molecule to a functional alkoxysilane monomer to generate covalently bound imprint precursor. This precursor was incorporated into a cross‐linked functional silica sol with the tetraethoxysilane as cross‐linker via a typical acid‐catalyzed, sol‐gel synthesis. Then, the SCIM was prepared through dipping and grafting on the upper side and inner pores of the Al2O3 microporous membrane and then removing of the template molecule after thermal treatment. Compared with composite imprinted membrane via noncovalent imprinting approach as well as the black Al2O3 microporous membrane, the SCIM exhibited higher membrane flux and selective rebinding of p‐HB as well as showing excellent permeability for p‐HB. Response surface methodology was used to investigate the best combination of separation conditions in the dynamic separation process. The optimal conditions for the separation of p‐HB from salicylic acid were as follows: the p‐HB concentration of 5 mg L−1, the temperature of 10°C, and the flow rate of 1 mL min−1. Under these conditions, the experimental selective separation factor was 32.75 ± 0.91%, which was close to the predicted selectivity coefficient value. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40621.

Isolation and determination of estrogens in water samples by solid-phase extraction using molecularly imprinted polymers and HPLC

Advanced SPE with molecularly imprinted polymers (MIP) was used in this study. A noncovalent imprinting approach was applied to separate 17β-estradiol, estriol, and estrone from water samples. Polymer material was prepared by bulk polymerization with methacrylic acid as a functional monomer, divinylbenzene and ethyleneglycol dimethacrylate as crosslinkers, and acetonitrile, acetonitrile/toluene (3:1, v/v) or isooctane/toluene (1:99, v/v) as a porogen. We also prepared an MIP film on a silica gel surface with methacrylic acid and ethyleneglycol dimethacrylate as monomers and acetonitrile as a solvent. Qualitative and quantitative hormone analyses were carried out by HPLC with various detection techniques, including UV/visible spectroscopic detection (diode array detection) and electrochemical detection (CoulArray). The results of the study indicate that MIP technology is an excellent method for the quality control of estrogens in environmental analyses with a low quantification limit for 17β-estradiol of around 26 (diode array detection) and 0.25 ng/mL (electrochemical detection). The proposed method was found to be suitable for routine determinations of the analyzed compound in environmental laboratories.

Development of Molecularly Imprinted Polymers (MIPS) nano particles for the selective determination of Carbamazepine in human serum and plasma

A new, simple, rapid, and sensitive solid-phase extraction with molecularly imprinted polymer (SPE-MIP) for determination of Carbamazepine in biological samples was developed. These nano particle polymers were synthesized via a non-covalent molecular imprinting approach through precipitation polymerization method using methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker agent, carbamazepine as a target template molecule and azobisisobutyronitrile (AIBN) as an initiator. The optimal conditions for SPE consisted of conditioning the cartridge using a pH=3.0 water, loading 5.0 ml of the sample under basic aqueous conditions, clean-up using 2×2ml acetonitrile and elution with 3.0 ml methanol. After optimization of SPE procedure, an aliquot of extracted template was injected to the ACE, 5μm 250×4.6 mm analytical column with the mobile phase as the same as elution solvent. This method was used for extraction of carbamazepine from an anticonvulsant aqueous solution and the results revealed an extraction recovery of more than 90%. HPLC chromatograms show an efficient clean up, which supports the potential of MISPE for clean-up of trace amounts of carbamazepine from the drug formulation.

Development of Molecularly Imprinted Polymers (MIPs) Nano Particles for the Selective Determination of Carbamazepine in Human Serum and Plasma

A new, simple, rapid, and sensitive solid-phase extraction with molecularly imprinted polymer (SPE-MIP) for determination of Carbamazepine in biological samples was developed. These nano particle polymers were synthesized via a non-covalent molecular imprinting approach through precipitation polymerization method using methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker agent, carbamazepine as a target template molecule and azobisisobutyronitrile (AIBN) as an initiator. The optimal conditions for SPE consisted of conditioning the cartridge using a pH=3.0 water, loading 5.0 ml of the sample under basic aqueous conditions, clean-up using 2×2ml acetonitrile and elution with 3.0 ml methanol. After optimization of SPE procedure, an aliquot of extracted template was injected to the ACE, 5μm 250×4.6 mm analytical column with the mobile phase as the same as elution solvent. This method was used for extraction of carbamazepine from an anticonvulsant aqueous solution and the results revealed an extraction recovery of more than 90%. HPLC chromatograms show an efficient clean up, which supports the potential of MISPE for clean-up of trace amounts of carbamazepine from the drug formulation.

Studies of the Molecular Recognition Abilities of Gallic Acid-Imprinted Polymer Prepared Using a Molecular Imprinting Technique

The present work compares the molecular recognition abilities of two molecularly imprinted polymers (MIPs) synthesized using two different functional monomers, viz. acrylamide (AA) and 4-vinylpyridine (4-Vp), employing gallic acid (GA) as the template using the non-covalent imprinting approach employing ethylene glycol dimethacrylate (EGDMA) as the cross-linker and 2,2-azo-bis-2-isobutyronitrile (AIBN) as an initiator in the porogen acetonitrile by thermal polymerization. The change in the electronic stabilization energies (ΔE) of the template–monomer complexes formed between the template and functional monomers in the presence of the porogen were computed using Density Functional Theory (DFT) to interpret the nature of the interactions between them and to compare their stabilities. A systematic investigation of the molecular recognition abilities of the synthesized MIPs has been carried out by applying the Langmuir–Freundlich (L–F) adsorption isotherm model. The binding parameters obtained from the L–F model demonstrate that MIPAA exhibited a higher specific molecular recognition ability towards the template molecule.