Maximum Binding Amount Research Articles

Properties, evaluation and application of naringin magnetic molecularly imprinted polymer based on synergistic imprinting strategy.

A novel and facile surface molecularly imprinted polymer coated on magnetic chitosan (Fe3O4@CS@MIP) was fabricated for the selective recognition and enrichment of naringin (NRG). The Fe3O4@CS@MIP was prepared based on covalent-noncovalent synergistic imprinting strategies, utilizing 4-vinyl phenyl boric acid as covalent functional monomer, deep eutectic solvent (choline chloride/methacrylic acid [ChCl/MAA]) as non-covalent functional monomer and Fe3O4@CS nanoparticles as the magnetic support. The obtained Fe3O4@CS@MIP exhibited a uniform morphology, excellent crystallinity, outstanding magnetic properties, and high surface area. Owing to the double recognition abilities, the resultant polymer showed exceptional binding performance and rapid mass transfer in phosphate buffer (pH 7.0). The maximum binding amount of Fe3O4@CS@MIP was found to be 15.08mgg-1, and the equilibrium adsorption could be achieved within 180min. Moreover, they also exhibited stronger selectivity for NRG and satisfactory reusability, with only 11.0% loss after five adsorption-desorption cycles. Additionally, the Fe3O4@CS@MIP, serving as an adsorbent, presented practical application potential in the separation and enrichment of NRG from pummelo peel, with extraction efficiency in the range of 79.53% to 84.63%. This work provided a new strategy for improving the performance of MIP and contributed an attractive option for the extraction of NRG in complex samples.

The structural and functional properties of hemp protein isolate-epigallocatechin-3-gallate biopolymer covalent complex during heating.

It is well known that hemp proteins have the disadvantages of poor solubility and poor emulsification. To improve these shortcomings, an alkali covalent cross-linking method was used to prepare hemp protein isolate-epigallocatechin-3-gallate biopolymer (HPI-EGCG) and the effects of different heat treatment conditions on the structure and emulsifying properties of the HPI-EGCG covalent complex were studied. The secondary and tertiary structures, solubility, and emulsification ability of the HPI-EGCG complexes were evaluated using particle size, zeta potential, circular dichroism (CD), and fluorescence spectroscopy indices. The results showed that the absolute value of zeta potential of HPI-EGCG covalent complex was the largest, 18.6 mV, and the maximum binding amount of HPI to EGCG was 29.18 μmol g-1 . Under heat treatment at 25-35 °C, the α-helix content was reduced from 1.87% to 0%, and the β-helix content was reduced from 82.79% to 0% after the covalent binding of HPI and EGCG. The solubility and emulsification properties of the HPI-EGCG covalent complexes were improved significantly, and the emulsification activity index (EAI) and emulsion stability index (ESI) were increased by 2.77-fold and 1.21-fold, respectively. A new HPI-EGCG covalent complex was developed in this study to provide a theoretical basis for the application of HPI-EGCG in food industry. © 2023 Society of Chemical Industry.

Design and investigation of targeting agent orientation and density on nanoparticles for enhancing cellular uptake efficiency.

The design of targeting agent-conjugated systems is attracting much attention in cell targeted delivery and cancer therapy. However, quantitative study of the ligand density and binding efficiency is still limited due to the technical matters and tedious work involved. In this article, benzoboroxole-modified core-shell magnetic nanoparticles (MSP-AOPB NPs) as a drug carrier model were fabricated and transferrin (Tf) was immobilized on the nanoparticle surface in a site-oriented manner (Tf-MSP-AOPB NPs). The preparation conditions were investigated in detail to optimize the Tf binding efficiency. A suitable reaction temperature, time or initial feeding amount could significantly increase the Tf binding amount. The maximum Tf binding amount on the MSP-AOPB NPs was 184 mg g-1, and the targeting ligand density on the surface could be well controlled by simply adjusting the reaction conditions. In vitro studies demonstrated the excellent Tf-mediated targeting ability and enhanced cellular uptake efficacy by varying the ligand density. The optimal ligand binding amount for achieving the highest cellular uptake efficiency was 94 mg Tf/g, which corresponds to a ligand binding density of about 0.05 Tf/nm2, and the binding efficiency of conjugation was higher than 90%. Moreover, Tf-MSP-AOPB NPs prepared by a site-oriented conjugation strategy showed the best cell targeting ability, and their cellular uptake amount was 25 and 127 times higher than that of physical adsorption and EDC/NHS coupling reaction in HepG2 cells, respectively. This study provides a facile site-oriented bioconjugation technique for different kinds of antibodies, and a suitable ligand density can be easily attained to enhance the cellular uptake efficacy, which shows great significance for targeted delivery and cancer therapy.

Efficient separation of aristolochic acid I from Caulis aristolochiae manshuriensis (Guan-mu-tong) with copper mediated magnetic molecularly imprinted polymer.

Screening bioactive compounds from natural products is one of the most effective ways for new drug research and development. However, obtaining a single extract component on a large scale and with high purity from a complex matrix is still an arduous and challenging task. Herein, one metal mediated magnetic molecularly imprinted polymer (mMIP) was rationally designed and prepared for specifically capturing Aristolochic acid I (AAI). The preparation was done with copper(II) as binding pivot, (3-aminopropyl) triethoxysilane as functional monomer, and Fe3O4 as core, by a one-step sol-gel method. Under the optimized conditions, the apparent maximum binding amount of copper mediated mMIP (Cu-mMIP) reaches as high as 349.72 mg g-1, the highest among the reported AAI-MIPs. Moreover, the nanoparticles exhibit excellent specificity and selectivity, good reproducibility and stability, high superparamagnetism (60.32 emu g-1), and high imprinting efficiency (an imprinting factor of 7). By simulating an industrial-scale separation, 16.56 mg AAI (purity of 95.11%) is obtained after six cycles with 100 mg nanoparticles from 20 g Caulis aristolochiae manshuriensis (Guan-mu-tong). Notably, this takes only 3 hours and consumes 50 mL of methanol. The study provides a potent tool for the green, fast, and specific extraction of high-purity ingredients from natural plants in the manufacturing industry and conventional analysis in the lab.

Strategies for selection and identification of rabbit single-chain Fv antibodies as ligand in affinity chromatography

We developed affinity chromatographic resins that immobilized rabbit single-chain Fv antibodies (scFvs). By biopanning using antigen-coupled multilamellar vesicles (Ag-MLVs), 152 types of original scFv clones that specifically bind to human IgG were isolated and identified. Apparent dissociation rate constants, appkoff, of six different candidates were less than 10-3 s-1 and their dissociation constants, KDs, were ranged from 5.56× 10-10 to 4.04× 10-8M. Consequently, the clones, R1-27, R2-18, and R3-26 were further investigated for use in affinity purification of human IgG. Both the clones, R1-27 and R3-26 maintained more than 40% of antigen-binding activities on the surface of affinity resins. Especially, R3-26 had a relatively high alkaline resistance. The direct separation of human IgG from 10% FBS-D-MEM by use of the column with R1-27 achieved 97.2% purity, while the column with R3-26 showed almost 100% recovery. The affinity resins at the densities between 4.32 and 15.19mg-scFv/cm3 exhibited maximum binding amount of human IgG, while the highest ligand utilization was achieved by use of the resin at approximately 9mg-scFv/cm3. The resin exhibited 7.69mg/cm3 of equilibrium binding capacity (EBC) in affinity chromatography. It was expected that the EBC of affinity resins was strongly dependent on the specific surface area as well as the pore volume of the base resin. Therefore, the strategies to develop affinity ligands will be beneficial for development of on-demand affinity columns with higher affinity/selectivity, chemical resistance, while optimization of pore size and pore volume for scFv-coupled resins will further improve the EBC.

Introduction of chlorogenic acid during extrusion affects the physicochemical properties and enzymatic hydrolysis of rice flour

To investigate how chlorogenic acid (CHA) affects the physicochemical properties and hydrolysis of rice flour during extrusion. CHA was extruded with rice flour through a twin-screw extruder at different concentrations (0–2.0%), and the physicochemical properties of the extrudates, including crystallinity, pasting properties and CHA binding, were characterized through X-ray diffraction, Fourier-transform infrared spectroscopy, Rapid Visco Analyzer and ultraviolet spectrophotometer. Particularly, starch hydrolysis and the release of CHA were also evaluated through enzymatic hydrolysis and high-performance liquid chromatography. Results indicated that the addition of CHA promoted the formation of V-type crystals and increased the orderliness of the complexes. The maximum binding amount of CHA in extrudates was 10.98 mg/g without any isomerization or degradation. Additionally, the rapidly digestive starch (RDS) decreased markedly (down to 41.28 ± 2.66%), and there was a pronounced increase in resistant starch (RS), which varied from 10.28 ± 2.62 to 31.16 ± 0.50% in different extrudates. Our results indicated that CHA yielded a negative effect on starch hydrolysis and might provide basic guidance for the application of CHA to healthy starchy food processing in the future.

One-step synthesis of functional metal organic framework composite for the highly efficient adsorption of tylosin from water

Functional metal organic framework composite can effectively remove antibiotics from environmental water samples. However, designing excellent adsorbents with multiple active sites via a rapid one-step method is still a challenging problem. A novel metal organic framework composite (UiO-66-NH2-AMPS) was synthesized through one-step polymerization by adding functional monomer 2-acrylamide-2-methylpropanesulfonic acid (AMPS) during the preparation of UiO-66-NH2. The microstructure and morphology of the UiO-66-NH2-AMPS composite were characterized, and the adsorption performance towards tylosin (TYL) in water was explored by equilibrium adsorption experiment. The results illustrated that the adsorption equilibrium can be reached within 1 h, and the maximum binding amount of UiO-66-NH2-AMPS for TYL was 161.60 mg g−1, which was approximately 2.1–329 times of that of the other adsorbents. The pseudo second-order kinetic and Liu isotherm model were suitable for the adsorption process, and thermodynamic study displayed that the adsorption of UiO-66-NH2-AMPS composite for TYL is spontaneous and endothermal. The infrared and X-ray photoelectron spectra exhibited that hydrogen bond and electrostatic interaction were the primary recognition force for TYL. The UiO-66-NH2-AMPS composite have been successfully applied to remove TYL from environmental water. After 5 cycles, the removal efficiency of UiO-66-NH2-AMPS was still above 91.30%.

Potential allergenicity assessment after bovine apo-α-lactalbumin binding to calcium ion.

Bovine α-lactalbumin (α-LA) is recognized as a major milk allergen. Generally, α-LA in the natural state combines with a calcium ion, however, some studies have shown that calcium ions can binding the other metal binding sites in α-LA as well. In our study, the optimal condition of calcium ion binding to α-LA and the change of structure and allergenicity were explored. By optimizing the conditions, the maximum calcium binding amounts of apo-α-LA were obtained in a ratio of 1:4. The structure of α-LA after removal of calcium obviously changed by the spectroscopic detection. For the digestive stability, there was no obvious change in three forms of α-LA. While the allergenic properties were characterized by IgG/IgE inhibition ELISA and the human basophil KU812 degranulation assay. The results showed that IgG and IgE binding decreased, and the degranulation capacity of basophils weakened. Based on these results, calcium binding to apo-α-LA can reduce the potential allergenic properties. PRACTICAL APPLICATIONS: By optimizing the conditions, bovine apo-α-LA can obtain the most calcium binding amount. And calcium binding to apo-α-LA can reduce the potential allergenic properties. Compared with α-LA in the natural state, calcium binding to α-LA not only can reduce the allergenic properties, but also play a role in calcium supplementation. It might be used to guide the development of hypoallergenic α-LA and provide a method to reduce the potential allergenic properties of α-LA.

One-step polymerization of hydrophilic ionic liquid imprinted polymer in water for selective separation and detection of levofloxacin from environmental matrices.

A novel green hydrophilic levofloxacin imprinted polymer was presented via one-step polymerization in water using ionic liquid 1,6-hexa-3,3'-bis-1-vinylimidazolium bromine with multiple hydrophilic groups and 2-hydroxyethyl methacrylate as a co-functional monomer. Adsorption experiment revealed that the ionic liquid significantly improved the water compatible of imprinted polymer, and the excellent recognition of molecularly imprinted polymer for levofloxacin in water corresponds to the synergetic effect of H-bonding and the electrostatic and π-π interactions between the levofloxacin and co-functional monomer. Furthermore, the adsorption process of the imprinted material towards levofloxacin fitted the Langmuir model, and the maximum binding amount of levofloxacin onto the imprinted and corresponding non-imprinted polymer were 16.45 and 6.82mg/g at 25°C, respectively. After optimizing the parameters affecting solid phase extraction performance, an enrichment and determination system was achieved to separate and detect levofloxacin from water and sediment samples with recoveries that ranged from 83.67 to 101.33% and relative standard deviation of less than 5.59%.

The first characterization of a Ca2+-dependent carbohydrate-binding module of β-1,3-xylanase from Flammeovirga pacifica

A novel carbohydrate binding module (CBM) was identified in a β-1,3-xylanase from Flammeovirga pacifica, which showed only 25.0% sequence identity with the reported CBMs with the coverage of 36.4%. To verify its function, a truncated β-1,3-xylanase (Xy13088-T) and a carbohydrate binding module (CBM3088) were expressed and purified. The thermostability and catalytic efficiency of the Xy13088-T declined significantly when compared with the full-length one, with the decreasing of the half-life and catalytic efficiency (Kcat/Km) by 90%. Interestingly, the CBM3088 showed the binding ability to β-1,3-xylan only when Ca2+ existed, which was different from the reported CBMs of β-1,3-xylanases. The maximum amount of CBM3088 binding to β-1,3-xylan was 9.65 μmol/g of β-1,3-xylan. The residues probably involved in the binding to the β-1,3-xylan and Ca2+ were addressed by bioinformatics analysis.

2-(Allyloxy) methylol-12-crown-4 ether functionalized polymer brushes from porous PolyHIPE using UV-initiated surface polymerization for recognition and recovery of lithium

It is highly desirable to develop an efficient adsorbent with large capacity, high selectivity and fast kinetics to recovery virtually inexhaustible lithium ion (Li+) resources from salt lake brine. In this work, 2-(allyloxy) methylol-12-crown-4 ether (2AM12C4) functionalized polymer brushes (PVBC-g-PCE) from macroporous polymeric high internal-phase emulsion (PolyHIPE) using UV-initiated surface polymerization are synthesized for selectively recovery of Li+. PVBC-g-PCE possesses the advantages of strong physical strength, high density of accessible binding sites, and the size of highly permeatable voids and interconnecting pores is about 8.0–18 µm and 3.3–4.8 µm, respectively, which is a favorable adsorbent for specific capture Li+. PVBC-g-PCE has a maximum capacity at pH 6.0, and the pH-dependent adsorption amount suggests the grafted polymer brushes of 2AM12C4 is the driving force to enhance binding performance. PVBC-g-PCE has a fast adsorption equilibrium within 45 min, and the kinetic results are well-described by the pseudo-second-order model, indicating the specific host-guest interaction between functionalized 2AM12C4 and Li+ is the main adsorption mechanism. Moreover, the maximum monolayer binding amount of PVBC-g-PCE is 4.43 mg g−1, and the strong affinity in the presence of four kinds of interfering ions (i.e. Na+, K+, Mg2+, and Ca2+) is also observed, which can also be proved by the high relative selectivity separation coefficient (αr) between 3.16 and 7.98. It is expected that this PVBC-g-PCE with abundant easy-to-access specific recognition sites can be applied as a promising adsorbent for effective separation of Li+.

Chitin‐halloysite nanoclay hydrogel composite adsorbent to aqueous heavy metal ions

ABSTRACTHalloysite nanoclay (HNC) was mixed with Chitin hydrogel film by phase inversion in water vapor atmosphere at room temperature. In the preparation, Chitin was dissolved in N,N‐dimethyl acetamine/lithium chloride (DMAc/LiCl) and different amounts of HCN was dispersed well for the gelation process. The resultant Chitin‐Halloysite nanoclay (CTH) hydrogel films containing HCN at 0, 0.1, 0.5, 1, and 4 wt % were used for the adsorbents of heavy metal ions. As the results, the tensile strength of the hydrogel composite was enhanced from 0.34 to 0.71 N/mm2 while the elongation decreased from 66.43% to 49.93% with the increment of HNC concentration from 0 to 4 wt %. A reduction in the water content and the increment in the modulus confirmed the formation of highly dispersed nano‐composites with improved interfacial interactions between nano‐fillers and matrix. In the adsorption experiments of the ternary ion of Pb2+, Cu2+, and Cd2+, the removal capacity of Pb(II) was highly retained by the CTH hydrogel film relative to Cd(II) and Cu(II), shown Langmuir model with the maximum binding amount on the hydrogel composites were followed as order Pb (8.2 mg/g), Cu (4.2 mg/g), and Cd (2.1 mg/g). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47207.

Characterization of binding behaviors of Cd2+ to rice proteins

In this paper, for the first time the binding behavior of cadmium (Cd2+) to rice proteins (RPs) was studied. The results showed that the equilibrium of binding was reached within 30 min at 303 K with a maximum binding amount (q) of 15.26 mg/g, and the pH was an important factor positively influencing q. At both 308 K and 313 K, the binding of Cd2+ to RPs belonged to spontaneous, endothermic interactions with high-affinity, assigned to a multidentate coordination. Except for acetate, all the investigated competing coordination agents, such as edetate, pyrophosphate and citrate, showed inhibitory effects on RPs-Cd2+ binding, and edetate seemed to be the most effective one. At pH 6.5, calcium, copper and zinc began to restrict RPs-Cd2+ binding when the metal ion concentration reached 500 mg/kg, and the decreasing of pH would strengthen the inhibitory effects of the investigated metal ions including ferric ions.

Fabrication of Calixarene Based Protein Scaffold by Electrospin Coating for Tissue Engineering

In this study, calixarene was synthesized by using different functional groups as p-tert-butyl-Calix[4]arene ester and amides. Calixarene nanofibers were produced by electrospin coating. Protein immobilization onto the calixarene nanofibers was carried out with human serum albumin (HSA). The maximum amount of binding on produced three different calixarene nanofibers (DE, 2-AMP and 3-AMP) was compared by using a fluorescence technique for protein analysis. Result showed that maximum binding amount was found to be as 177.85 mg cm-2 for 3-AMP surface. The protein binding was also characterized by using SEM, TEM, AFM and FT-IR. From obtained results, calixarene-albumin nanofiber was also fabricated by spin coating using 3-AMP which has ability max binding of protein.

Dual-template magnetic molecularly imprinted particles with multi-hollow structure for the detection of dicofol and chlorpyrifos-methyl.

In this work, a novel dual-template magnetic molecularly imprinted polymer particle for dicofol and chlorpyrifos-methyl was prepared through oil-in-water emulsifier-free emulsion technology. The resulting magnetic particles were characterized with electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. It was found that as-prepared particles were well-shaped spheres with multi-hollow structures and of a size around 125 μm. Meanwhile it showed a good magnetic sensitivity. The results testified that multi-hollow magnetic molecularly imprinted polymers possessed excellent recognition capacity and fast kinetic binding behavior to the objective molecules. The maximum binding amounts toward dicofol and chlorpyrifos-methyl were 31.46 and 25.23 mg/g, respectively. The feasibility of the use of the particles as a solid-phase extraction sorbent was evaluated. Satisfactory recoveries ranging from 90.62 to 111.47 and 91.07 to 94.03% were obtained for dicofol and chlorpyrifos-methyl, respectively, spiked at three concentration levels from real samples. The Langmuir isotherm equation provided an excellent fit to the equilibrium sorption data of either dicofol or chlorpyrifos-methyl. It provided a novel way to advise dual-template magnetic molecularly imprinted polymer particles to adsorb pesticides with high selectivity.

Preparation and characterization of imprinted microspheres for clopyralid

In this work, the molecularly imprinted polymers (MIPs) and non-imprinted polymers (NIPs) for clopyralid (3,6-DCP) were successfully synthesized via precipitation polymerization using methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinker and a mixture of butanone (MEK) and n-heptane as porogen under the existence of azobisisobutyronitrile (AIBN). The morphologies, particle sizes, structures, adsorption properties and selective recognitions of polymers were investigated systematically. The average particle sizes of MIP3 and NIP3 were 2.76 μm and 2.15 μm. The apparent maximum binding amount (Qmax) of MIP3 and NIP3 were 67.50 mg·g−1 and 65.02 mg·g−1 in Scatchard analysis. Langmuir isotherm displayed that the Langmuir constant (Kl) of MIP3 and NIP3 were 0.015 L·mg−1 and 0.0065 L·mg−1, the saturation adsorption capacity (Qmax) of MIP3 and NIP3 were 63.23 mg·g−1 and 58.17 mg·g−1. Lagergren pseudo-second-order kinetic plot described that the adsorption process of MIP3 was visualized as chemical absorption. Selectivity analysis revealed that MIP3 possessed highly specific recognition for 3,6-DCP.

3-O-Acyl-epicatechins Increase Glucose Uptake Activity and GLUT4 Translocation through Activation of PI3K Signaling in Skeletal Muscle Cells.

Tea catechins promote glucose uptake in skeletal muscle cells. In this study, we investigated whether the addition of an acyl group to the C-3 position of catechins to generate 3-O-acyl-catechins promoted glucose uptake in L6 myotubes. 3-O-Myristoyl-(−)-epicatechin (EC-C14) and 3-O-palmitoyl-(−)-epicatechin (EC-C16) promoted glucose uptake and translocation of glucose transporter (GLUT) 4 in the cells. The effect of 3-O-acyl-(−)-epicatechins was stronger than that of (−)-epicatechin (EC), whereas neither 3-O-myristoyl-(+)-catechin (C-C14) nor 3-O-palmitoyl-(+)catechin (C-C16) promoted glucose uptake or GLUT4 translocation as well as (+)-catechin (C). We further investigated an affinity of catechins and 3-O-acyl-catechins to the lipid bilayer membrane by using surface plasma resonance analysis. Maximum binding amounts of EC-C16 and C-C16 to the lipid bilayer clearly increased compared with that of (−)-EC and (+)-C, respectively. We also examined the mechanism of GLUT4 translocation and found EC-C14 and EC-C16 induced the phosphorylation of PI3K, but did not affect phosphorylation of Akt or IR. In conclusion, the addition of an acyl group to the C-3 position of (−)-EC increases its affinity for the lipid bilayer membrane and promotes GLUT4 translocation through PI3K-dependent pathways in L6 myotubes.

Selective and sensitive determination of erythromycin in honey and dairy products by molecularly imprinted polymers based electrochemical sensor

A highly selective and sensitive sensor has been developed for the determination of erythromycin (ERY) using molecularly imprinted polymers (MIPs) based electrochemical sensor. MIPs were adapted as a selective recognition element for enhancing the selectivity and sensitivity of the proposed electrochemical sensor. MIPs were synthesized and then used for the preparation of MIPs modified carbon paste (MIPs-CP) electrode. Our synthesized MIPs exhibited high adsorption capacity to ERY, with maximum binding amount (Qmax) of 93.5mgg−1 and imprinting factor (IF) of 2.1. Subsequently, the prepared electrode was used for quantitative determination of ERY by differential pulse voltammetry (DPV) method. The MIPs-CP electrode exhibited an excellent current response toward ERY, compared with non-imprinted polymers modified carbon paste (NIPs-CP) electrode. Furthermore, for structurally similar compounds, MIPs-CP electrode possessed to be highly selective for ERY. Under the optimum conditions, the linear calibration range was 5.0×10−8–1.0×10−5molL−1, and the limit of detection (LOD) of the sensor was 1.9×10−8molL−1. The developed sensor was successfully applied for analyzing ERY in honey and dairy products. Benefiting from the great selectivity and sensitivity, the developed sensor demonstrates a promising potential for practical application for analyzing ERY residues in foodstuffs.

Preparation of Isoprocarb Surface Molecular-Imprinted Materials and Its Recognition Character

Abstract The silylating agent 3-methacryloxypropyl trimethoxysilane (MPS) was grafted on the surface of silica gel particles, then the molecular imprinting was carried out by using isoprocarb as template, methylacrylic acid (MAA) as functional monomer and ethylene glycol diglycidyl ether (EGDE) as crosslinker in the ethanol solution, and then the surface-molecular imprinted materials of isoprocarb (MIP-PMAA-MPS-SiO2) was obtained. The binding properties of MIP-PMAA-MPS-SiO2 for isoprocarb were studied with both static and dynamic methods. The experiment results showed that MIP-PMAA-MPS-SiO2 had specific recognition selectivity and excellent binding selectivity for the template molecule. In respect to the reference substance tsumacide and carbaryl, its selectivity coefficient for isoprocarb was 6.73 and 8.95, respectively. The relative selectivity coefficient was 4.43. After the Scatchard analysis, Qmax (the apparent maximum binding amount) values were calculated to be 229.6 and 116.7 mg g−1, respectively, and the dissociation constant (Kd) values were calculated to be 1428.6 and 476.2 mg L−1, respectively. Besides, the spiked recovery in rape samples experiment showed that imprinted material of MIP-PMAA-MPS-SiO2 can enrich and separate for trace amounts of isoprocarb, and it was also easy to be used repeatedly.

Flow injection chemiluminescence sensor using core-shell molecularly imprinted polymers as recognition element for determination of dapsone

This paper reports the preparation of dapsone (DDS) imprinted polymer layer-coated silica submicron particles (SiO(2)) combined with chemiluminescence (CL) toward analysis of tracing DDS in practical samples. To induce the selective occurrence of surface polymerization, the amino groups were first grafted at the surface of SiO(2) by the (3-aminopropyl)triethoxysilane (APTES). The molecularly imprinted polymers (MIP) were coated at the surface of modified SiO(2) by the graft copolymerization. After the removal of templates, recognition sites of DDS were exposed in the polymer layers. The DDS-imprinted products were characterized by FT-IR, SEM, TEM, dynamic adsorption, and static adsorption tests. The proximity between the thickness of MIP layer and the spatial size of DDS indicated that the imprinted sites almost situated at the surface of MIP, leading to rapid adsorption saturation within 90 min. The apparent maximum binding amount of MIP toward DDS was evaluated as 14.98 mg·g(-1), which was much higher than that of non-molecularly imprinted polymers. The CL sensor provided a wide linear range for DDS within 1.0 × 10(-6) to 1.0 × 10(-4) mol·L(-1) with a detection limit of 5.27 × 10(-7) mol·L(-1) and the relative standard deviation of 1.8 % (n = 11) by determinations of 5.0 × 10(-6) mol·L(-1) DDS. This method was applied to determine DDS in urine samples and satisfactory results were obtained.