Ion-imprinted Polymer Nanoparticles Research Articles

Development of an ultrasensitive electrochemical genosensor for detection of HIV-1 pol gene using a gold nanoparticles coated carbon paste electrode impregnated with lead ion-imprinted polymer nanomaterials as a novel electrochemical probe

In this work, we developed a simple and label-free voltammetric genosensor to determine the HIV-1 pole gene by using lead ion-imprinted polymer (Pb-IIP) nanoparticles as a novel electrochemical probe. For this purpose, a carbon paste electrode (CPE) was impregnated with lead ion-imprinted polymer nanoparticles. Lead ions were reduced and accumulated onto the surface of CPE at − 1.0 V vs. Ag/AgCl and, then, Au nanoparticles (AuNPs) were electrochemically deposited on the surface of Pb-IIP-CPE. The modified AuNPs/Pb-IIP-CPE electrode showed a well-defined lead oxidation peak with excellent stability and reproducibility. Finally, the thiol-DNA probe of HIV-1 pole gene was immobilized on the surface of the modified electrode through a self-assembly method. Due to the blocking of lead electron transfer at the electrode surface with the probe DNA immobilization, the Pb oxidation peak current was decreased. In the end, upon the hybridization of probe DNA with the target DNA, the response current of the electrochemical probe was further decreased. Under optimum conditions, the developed genosensor showed a linear detection range from 1 fM to 0.1 nM, with a detection limit of 0.3 fM (S/N = 3).

Electrochemical preconcentration of ultra-trace Cd2+ from environmental and biological samples prior to its determination using carbon paste electrode impregnated with ion imprinted polymer nanoparticles

ABSTRACTCadmium (Cd) is known as one of the most toxic elements among the heavy metals. This study proposes an electrochemical preconcentration method using the ion imprinted polymer nanoparticles modified carbon paste electrode (IIP-CPE) for the stripping voltammetry determination of Cd2+ in the environmental and biological samples. These IIP NPs were synthesised using ethylene glycol dimethacrylate as the cross-linker, 2,2ʹ-azobisisobutyronitrile as the free radical initiator and 4ʹ-(4-vinylphenyl)-2,2ʹ:6ʹ,2ʺ-terpyridine as the Cd-binding ligand. The calibration plot was linear in the concentration range of 4–500 nM (R2 = 0.9936) with a sensitivity of 918 µA µM−1 cm−2. The LOD based on 3Sb/m (where m is the slope of the calibration curve and Sb is the standard deviation for five blank measurements) was found to be 1.94 nM. The relative standard deviations (RSDs) for single-electrode repeatability and electrode-to-electrode reproducibility were 3.0% and 5.6% (n = 5), respectively. The accuracy of the current method was confirmed by the analysis of urine quality control material (QCM, SeronormTM Trace Elements Urine, REF NO 201205, Norway) and spiked blood, rice and water samples. Recoveries were found to be above 95.0% for all samples, which confirms the good performance of the proposed voltammetry method.

Determination of subnanomolar levels of mercury (II) by using a graphite paste electrode modified with MWCNTs and Hg(II)-imprinted polymer nanoparticles

Mercury ion-imprinted polymer nanoparticles (Hg-IP-NPs) were synthesized via precipitation polymerization by using itaconic acid as a functional monomer. A carbon paste electrode was impregnated with the synthesized Hg-IP-NPs and MWCNTs to obtain a highly sensitive and selective electrode for determination of Hg(II). Mercury ion is first accumulated on the electrode surface via an open circuit procedure. After reduction of Hg(II) ions to its metallic form at a negative pre-potential, square wave anodic stripping voltammetry was applied to generate the electrochemical signal. The high affinity of the Hg-IP-NPs for Hg(II) was substantiated by comparing of the signals of electrodes with imprinted and non-imprinted polymer. The beneficial effect of MWCNTs on the voltammetric signal is also demonstrated. Under the optimized conditions andat a typical working potential of +0.05V (vs. Ag/AgCl), the electrode has a linear response in the 0.1-20nmol L-1 Hg(II) concentration range and a 29 pM detection limit. The electrochemical sensitivity is as high as 1441 A·M-1·cm-2 which is among the best values known. The electrode was applied to the determination of Hg(II) in water samples. Graphical abstract Schematic representation of thesensor electrode modified with mercury-imprinted polymer nanoparticles, and the recognition and voltammetric determination steps.

Synthesis of nano-sized hydrogen phosphate-imprinted polymer in acetonitrile/water mixture and its use as a recognition element of hydrogen phosphate selective all-solid state potentiometric electrode.

Herein, a new recipe is introduced for the preparation of hydrogen phosphate ion-imprinted polymer nanoparticles (nano-IIP) in acetonitrile/water (63.5:36.5) using phosphoric acid as the template. The nano-IIP obtained was used as the recognition element of a carbon paste potentiometric sensor. The IIP electrode showed a Nernstian response to hydrogen phosphate anion; whereas, the non-imprinted polymer (NIP)-based electrode had no considerable sensitivity to the anion. The presence of both methacrylic acid and vinyl pyridine in the IIP structure, as well as optimization of the functional monomers-template proportion, was found to be important to observe the sensing capability of the IIP electrode. The nano-IIP electrode showed a dynamic linear range of 1×10-5 -1×10-1 molL-1, Nernstian slope of 30.6±(0.5) mV decade -1 , response time of 25seconds, and detection limit of 4.0×10-6 mol L-1 . The utility of the electrodes was checked by potentiometric titration of hydrogen phosphate with La3+ solution.

Magnetic silver(I) ion-imprinted polymeric nanoparticles on a carbon paste electrode for voltammetric determination of silver(I)

Magnetic silver ion imprinted polymer nanoparticles (mag-IIP-NPs) were prepared and used as a recognition element in electrochemical detection of silver(I). The procedure involves two steps: (a) the extraction of the Ag(I) by the mag-IIP-NPs, and (b) determination of the preconcentrated Ag(I) ions on the surface of the magneto carbon paste electrode (MCPE) using differential pulse voltammetry. The amount of sorbent, pH value of the sample solution, extraction time, supporting electrolyte, reduction potential and reduction time were optimized. Under optimal conditions and at a working voltage of +0.02 V (vs. Ag/AgCl), the method displays a linear response in the 0.05 to 150 μg⋅L−1 Ag(I) concentration range. Other features include a low detection limit (15 ng⋅L−1), a remarkable selectivity and good reproducibility (with an RSD of 4.7%). The results obtained with this analytical assay when analyzing different water samples were compared with the data obtained by GF-AAS, and the results agreed satisfactorily. In our perception, this approach also may be extended to electrochemical detection for other ions, and this makes it a widely applicable strategy for heavy metal ion analysis.

Application of Ultrasonic Assisted-Dispersive Solid Phase Extraction Based on Ion-Imprinted Polymer Nanoparticles for Preconcentration and Trace Determination of Lead Ions in Food and Water Samples

In this paper, we describe ultrasonic assisted-dispersive solid phase extraction based on ion-imprinted polymer (UA-DSPE-IIP) nanoparticles for the selective extraction of lead ions. Ultrasound is a good and robust method to facilitate the extraction of the target ions in the sorption step and elution of the target ions in the desorption step. The ion-imprinted polymer nanoparticles used in the UA-DSPE-IIP were prepared by precipitation polymerization technique. The ion-imprinted polymer nanoparticles was synthesized using 2-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as the cross-linker, 2,2′- azobisisobutyronitrile as the initiator, 1,3,4-thiadiazole-2,5-dithiol as the ligand, methanol/dimethyl sulfoxide as the solvent, and lead as the template ion, through precipitation polymerization technique. The IIP nanoparticles were characterized by Fourier transformed infra-red spectroscopy (FTIR), thermogravimetric and differential thermal analysis (TGA/DTA), and scanning electron microscopy (SEM). Box-Behnken design (BBD) was used for optimization of sorption and desorption steps in UA-DSPE-IIP. In the sorption step: pH of solution, IIP amount (mg), sonication time (min) for sorption and in the desorption step: concentration of eluent (mol L−1), volume of eluent (mL), and sonication time (s) for desorption was investigated and optimized by the Box-Behnken design. The optimum conditions for the method were pH of solution: 7.5, sonication time for sorption 7.5 min, IIP amount 24 mg, type and concentration of eluent HCl 1.4 mol L−1, volume of eluent 2.1 mL, and sonication time for desorption 135 s. Under the optimized conditions, the limit of detection and relative standard deviation for the detection of lead ions by UA-DSPE-IIP was found to be 0.7 μg L−1 and <4%, respectively.

Novel potentiometric sensor for the trace-level determination of Zn2+ based on a new nanographene/ion imprinted polymer composite

ABSTRACTIn this research, a new strategy for construction of a development potentiometric carbon paste Zn2+-ion selective electrode based on a novel nano-sensing layer is suggested. The proposed nano-sensing layer was prepared with the addition of a synthesised Zn2+-ion imprinted polymer nanoparticles ‘as an efficient sensing agent’ into the carbon paste matrix consisting of graphite powder, nanographene-composite ‘graphene nanosheets decorated with silver nanoparticles’ and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ‘ an ionic liquid ’, as the conducting binder. Under the optimised experimental conditions, the suggested nanographene-composite potentiometric sensor presented a low detection limit of 1.93 × 10−1 μg L−1 and a linear analytical range from 2.62 × 10−1 to 6.54 × 105 μg L−1 with an excellent Nernstian slope of 29.80 mV decade−1. The proposed zinc selective sensor was successfully applied for the highly sensitive determination of trace amounts of Zn2+ in environmental and biological samples with satisfactory results.

Synthesis and application of novel ion-imprinted polymer coated magnetic multi-walled carbon nanotubes for selective solid phase extraction of lead(II) ions

In this study, novel magnetic ion-imprinted polymer (MIIP) nanoparticles were utilized for the sensitive and selective detection of Pb(II) ions by graphite furnace atomic absorption spectrometry (GFAAS). The Pb(II)-imprinted polymer was synthesized by using 4-vinylpyridine (4VP) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, 2,3,5,6-tetra(2-pyridyl) pyrazine (TPPZ) as the chelating agent and magnetic multi-walled carbon nanotubes (MMWCNTs) as the carrier. The synthesized MIIP materials were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). Various analytical parameters such as extraction and desorption time, eluent type and concentration, pH and sample volume were systematically examined. The selectivity of MIIP sorbent for Pb(II) ions in the presence of some cations was also evaluated. The limit of detection (LOD, 3Sb) and the relative standard deviation (RSD, n=8, c=25ngL−1) were found to be 2.4ngL−1 and 5.6%, respectively. The maximum sorption capacity of the MIIP for Pb(II) was found to be 48.1mgg−1. Finally, the proposed analytical procedure was successfully applied to monitoring lead in human hair and water samples with satisfactory results for the spiked samples.

Synthesis and application of ion-imprinted polymer nanoparticles for the extraction and preconcentration of mercury in water and food samples employing cold vapor atomic absorption spectrometry.

We describe a nanosized Hg(II)-imprinted polymer that was prepared from methacrylic acid as functional monomer, ethyleneglycol dimethacrylate as cross-linker, 2,2'-azobisisobutyronitrile (AIBN) as radical initiator, 2, 2'-di pyrydyl amine as a specific ligand, and Hg (II) as the template ions by precipitation polymerization method in methanol as the progeny solvent. Batch adsorption experiments were carried out as a function of pH, Hg (II) imprinted polymer amount, adsorption and desorption time, volume, and concentration of eluent. The synthesized polymer particles were characterized physically and morphologically by using infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopic techniques. The maximum adsorption capacity of the ion-imprinted and non-imprinted sorbent was 27.96 and 7.89 mg g(-1), respectively. Under optimal conditions, the detection limit for mercury was 0.01 μg L(-1) and the relative standard deviation was 3.2 % (n = 6) at the 1.00 μg L(-1). The procedure was applied to determination of mercury in fish and water samples with satisfactory results.

Synthesis and application of ion-imprinted polymer nanoparticles for the extraction and preconcentration of copper ions in environmental water samples.

Novel Cu(II) ion-imprinted polymers (Cu-IIP) nanoparticles were prepared by using Cu(II) ion-thiosemicarbazide complex as the template molecule and methacrylic acid, ethylene glycol dimethacrylate (EGDMA), and 2,2'azobisisobutyronitrile (AIBN) as the functional monomer, cross-linker, and the radical initiator, respectively. The synthesized polymer nanoparticles were characterized by using infrared spectroscopy (IR), thermo gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopic (SEM) techniques. Some parameters such as pH, weight of the polymer, adsorption time, elution time, eluent type, and eluent volume which affect the extraction efficiency of the polymer were studied. In the proposed method, the maximum sorbent capacity of the ion-imprinted polymer was calculated to be 38.8 mg g(-1). The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 80, 1.7%, and 0.003 μg mL(-1), respectively. The prepared ion-imprinted polymer nanoparticles have an increased selectivity toward Cu(II) ions over a range of competing metal ions with the same charge and similar ionic radius. The method was applied to the determination of ultra trace levels of Cu2+ in environmental water samples with satisfactory results.

Synthesis and application of ion-imprinted polymer nanoparticles for the determination of nickel ions

Novel Ni(II) ion-imprinted polymers (Ni-IIP) nanoparticles were prepared by using Ni(II) ion–1,5-diphenyl carbazide (DPC) complex as the template molecule and methacrylic acid, ethylene glycol dimethacrylate (EGDMA) and 2,2′-azobisisobutyronitrile (AIBN) as the functional monomer, cross-linker and the radical initiator, respectively. The synthesized polymer particles were characterized physically and morphologically by using infrared spectroscopy (IR), thermo gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopic (SEM) techniques. Some parameters such as pH, weight of the polymer, adsorption time, elution time, eluent type and eluent volume which affects the efficiency of the polymer were studied. The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 100, 1.9%, and 0.002μgmL−1, respectively. The prepared ion-imprinted polymer particles have an increased selectivity toward Ni(II) ions over a range of competing metal ions with the same charge and similar ionic radius. The method was applied to the determination of nickel in tomato and some water samples.

Application of a tailor-made polymer as a selective and sensitive colorimetric sensor for reliable detection of trace levels of uranyl ions in complex matrices

In this study, a new colorimetric chemosensor based on ion imprinted polymer nanoparticles was designed for quantitative detection of uranyl ions at trace levels in environmental water samples.

A simple and fast method based on new magnetic ion imprinted polymer nanoparticles for the selective extraction of Ni(ii) ions in different food samples

A schematic diagram for the synthesis process of magnetic ion imprinted polymer nanoparticles.

Application of Ion-Imprinted Polymer Nanoparticles for Selective Trace Determination of Palladium Ions in Food and Environmental Samples with the Aid of Experimental Design Methodology

A solid phase extraction method using Pd2+ ion-imprinted polymer (Pd2+-IIP) nanoparticles combined with flame atomic absorption spectrophotometry (FAAS) was developed for the preconcentration and trace detection of palladium ions. The Pd2+-IIP nanoparticles were obtained by precipitation polymerization of 4-vinylpyridine (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2′-azobisisobutyronitrile (the initiator), Eriochrome Cyanine R (the lead-binding ligand), and palladium ions (the template ion) in acetonitrile solution. The parameters affecting adsorption and desorption steps were optimized by a Box–Behnken design through response surface methodology. Three variables (pH value, extraction time, and amount of the synthesized IIP) were selected as the main factors affecting sorption step, while four variables (type of eluent, volume of the eluent, concentration of the eluent, and elution time) were selected for desorption step in the optimization study. The optimized values by this optimization method were 30 mg, 15 min, 6.0, HCl, 4.0 mL, 1.8 mol L-l HCl, and 14 min, for amount of polymer, retention time, pH of solution, type, volume, concentration of the eluent, and elution time, respectively. Under the optimized conditions, the detection limit for the proposed method was found to be 0.2 μg L−1, while the relative standard deviation (RSD) for five replicate measurements was calculated to be <3 %. Finally, the introduced solid phase extraction technique was successfully applied for extraction and determination of Pd2+ ions in food and environmental samples.

Synthesis and application of ion-imprinted polymer nanoparticles for the extraction and preconcentration of zinc ions

A new Zinc (II) ion-imprinted polymer (IIPs) nanoparticles was synthesised for the separation and recovery of trace Zn (II) ion from food and water sample. Zn (II) IIP was prepared by copolymerisation of methyl methacrylate (monomer) and ethylene glycol dimethacrylate (cross-linker) in the presence of Zn (II)-N,N′-o-phenylene bis (salicylideneimine) ternary complex wherein Zn (II) ion is the imprint ion and is used to form the imprinted polymer. Moreover, control polymer (NIP) particles were similarly prepared without the zinc (II) ions. The unleached and leached IIP particles were characterised by X-ray diffraction, Fourier transform infra-red spectroscopy and scanning electron microscopy. The preconcentration of Zn2+ from aqueous solution was studied during rebinding with the leached IIP particles as a function of pH, the weight of the polymer material, the uptake and desorption times, the aqueous phase and the desorption volumes. Flame atomic absorption spectrometry was employed for determination of zinc in aqueous solution.

Selective Solid-Phase Extraction and Trace Monitoring of Lead Ions in Food and Water Samples Using New Lead-Imprinted Polymer Nanoparticles

A solid-phase extraction method using Pb2+ ion-imprinted polymer (Pb2+-IIP) nanoparticles combined with flame atomic absorption spectrophotometry (FAAS) was developed for the preconcentration and trace monitoring of lead ions in environmental samples. The Pb2+-IIP nanoparticles were obtained by precipitation polymerization of 4-vinylpyridine (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2′-azobisisobutyronitrile (the initiator), 4-(2-pyridylazo) resorcinol (the lead-binding ligand), and lead ions (the template ion) in acetonitrile solution. The Pb2+-IIP nanoparticles were characterized by Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TGA/DTA), and by scanning electron microscopy (SEM). Different affecting parameters on the adsorption and desorption of this solid-phase extraction process were evaluated and optimized. Under the optimized conditions, the detection limit for the proposed method was found to be 0.9 μg L−1, while the relative standard deviation (RSD) for five replicate measurements was calculated to be <4 %. For proving that the proposed method is reliable, a range of food and water samples with different and complex matrices was used.

Synthesis and characterization of a novel nanostructured ion-imprinted polymer for pre-concentration of Y(iii) ions

A nanostructured Y(III) ion imprinted polymer (IIP) was synthesized by preparing a complex of Y(III) ions with 1,4-dihydroxy-9,10-anthraquinone (QZ) as a chelating agent. The Y(III) ion was found to form a 1 : 1 stable complex with QZ in 2-methoxyethanol solution. The prepared complex was then copolymerized with ethylene glycoldimethacrylate (cross-linking monomer), 2-hydroxyethyl methacrylate (functional monomer) and 2,2-azobis-isobutyronitrile (initiator) via a precipitation polymerization method. The imprinted Y(III) ion was removed using a 3 mol L−1 HCl solution to obtain leached IIP nanoparticles. Non-imprinted polymer particles were similarly prepared without Y(III) ions. The polymers were characterized by Fourier transform IR spectroscopy, scanning electron microscopy (SEM), dispersive X-ray spectroscopy, thermogravimetric analysis and N2 sorption–desorption isotherms. The SEM images of synthesized polymers exhibited nano-patterns. The effect of several parameters such as solution pH, sorption and desorption time, type, concentration, and volume of eluent on the extraction were investigated and optimized one variable at a time. The optimum pH for maximum sorption was 8.9. The maximum sorbent capacity of the IIP was 18.05 mg g−1. Following desorption, Y(III) was determined by inductively coupled plasma-atomic emission spectroscopy. A limit of detection and relative standard deviation (n = 6) of 0.9 ng mL−1 and 2.2%, respectively, were obtained. The method was applied in the determination of yttrium in a certified reference material and a radioyttrium sample to demonstrate the accuracy and applicability of the presented method.

Ion imprinted polymeric nanoparticles for selective separation and sensitive determination of zinc ions in different matrices

Preparation of Zn2+ ion-imprinted polymer (Zn-IIP) nanoparticles is presented in this report. The Zn-IIP nanoparticles are prepared by dissolving stoichiometric amounts of zinc nitrate and selected chelating ligand, 3,5,7,20,40-pentahydroxyflavone, in 15mL ethanol-acetonitrile (2:1; v/v) mixture as a porogen solvent in the presence of ethylene glycol-dimethacrylate (EGDMA) as cross-linking, methacrylic acid (MAA) as functional monomer, and 2,2-azobisisobutyronitrile (AIBN) as initiator. After polymerization, Cavities in the polymer particles corresponding to the Zn2+ ions were created by leaching the polymer in HCl aqueous solution. The synthesized IIPs were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, fluorescence spectroscopy and thermal analysis techniques. Also, the pH range for rebinding of Zn2+ ion on the IIP and equilibrium binding time were optimized, using flame atomic absorption spectrometry. In selectivity study, it was found that imprinting results increased affinity of the material toward Zn2+ ion over other competitor metal ions with the same charge and close ionic radius. The prepared IIPs were repeatedly used and regenerated for six times without any significant decrease in polymer binding affinities. Finally, the prepared sorbent was successfully applied to the selective recognition and determination of zinc ion in different real samples.

Flame photometric determination of cesium ion after its preconcentration with nanoparticles imprinted with the cesium-dibenzo-24-crown-8 complex

We report on the synthesis of cesium ion-imprinted polymer nanoparticles that were prepared by a precipitation polymerization strategy using dibenzo-24-crown-8 ether as a selective crown ether, methacrylic acid as the functional monomer, ethyleneglycol dimethacrylate as the crosslinker, and AIBN as the radical initiator. The prepared sorbents have a diameter of 50–90 nm and display highly selective binding capability for Cs(I) ion, with rapid adsorption and desorption. The maximum adsorption capacity is 50 mg g−1, and the preconcentration factor is around 100 at pH 9.0. Cesium ion was then determined by flame photometry with a detection limit (3σ) of 0.7 ng mL−1 and with a standard deviation of 0.9 %.