And 2,2-azobisisobutyronitrile Research Articles

Study on Organic Fluorine Modified Cationic Acrylic Resin and its Application in Cathodic Electrodeposition Coatings

The organic fluorine modified/containing cationic acrylic resin is prepared via solution polymerization technique using hexafluorobutyl methacrylate (HFMA) along with butyl acrylate (BA), methyl methacrylate (MMA), styrene (St), dimethylaminoethyl methacrylate (DMAEMA) and hydroxy propyl methacrylate (HPMA) as the comonomers, proprylene glycol monomethyl ether (PGME) as the solvent, and 2, 2-Azo-bis-iso-butyronitrile (AIBN) as the initiator. The synthesized resin in which fluorine atom is introduced into the polymer chains. The cathodic electrodeposition (CED) coatings were prepared by mixing the synthesized resin and blocked isocyanate. The influence of the amount of organic fluorine on the resin and the resultant CED coatings is investigated in detail. In view of the appearance and hydrophobicity of the film, the optimum amount of organic fluorine is obtained, which is 12.0%. The hydrophobicity and the acid and alkaline resistance properties of the coating film are improved when the organic fluorine monomer is introduced into the resin.

A simple and cost-effective synthesis route using itaconic acid to prepare a magnetic ion-imprinted polymer for preconcentration of Pb (II) from aqueous media

A new Pb (II) magnetic ion-imprinted polymer (Pb-MIIP) was successfully investigated for the selective extraction of Pb (II) from an aqueous solution. MIIP nanostructures were developed using itaconic acid-coated iron oxide nanoparticles (Fe3O4@ITA) as a novel magnetic core, ITA as a functional monomer and chelating agent, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, and 2,2-azobisisobutyronitrile (AIBN) as an initiator. The triple application of ITA in the synthesis and reduction of the number of compounds in the preparation of the MIIP, in addition to being economical, reduces the possibility of side reactions. The synthesized products were followed and confirmed in each step by instrumental and microscopic methods. The limit of detection of the Pb (II)-MIIP method was 0.21 μg L−1. Under the optimal conditions, the recovery (R%) was >90% with a relative standard deviation (RSD%) of <4.9%. The synthesized MIIP was reusable and successfully used to extract Pb (II) from tap water samples.

Preparation of fluorine and silicon modified cationic acrylic resin and its application in cathodic electrodeposition coatings

Purpose Fluorinated silicon polymers are expected to be adopted in specific coatings to afford outstanding advantages, such as high chemical and photochemical resistance, low surface tension and low refractive index. The modified acrylate resin is prepared via solution polymerization of fluorine and silicon monomers, acrylate monomers and other functional monomers. The purpose of this paper is that the fluorine and silicon monomers such as vinyltriethoxysilane (VTES) and hexafluorobutyl methacrylate (HFMA) and some cheap monomers such as styrene are used to prepare the cationic acrylic resin. Design/methodology/approach The fluorine and silicon modified cationic acrylic resin is prepared via solution polymerization technology, which uses butyl acrylate (BA), methyl methacrylate (MMA), styrene (St), HFMA, VTES, dimethylaminoethyl methacrylate (DMAEMA) and hydroxypropyl methacrylate (HPMA) as the co-polymerized monomers, propylene glycol monomethyl ether (PGME) as solvent and 2,2-Azo-bis-iso-butyronitrile (AIBN) as the initiator to create a resin to introduce the Si–O and C–F into the polymer chains. The cathodic electrodeposition (CED) coatings were prepared by mixing the synthetic resin and blocked isocyanate. Findings The influence of the amounts of HFMA and VETS on the resin and the resultant CED coatings is investigated in detail. The optimum amounts of HFMA and VETS are obtained, which is 7–8% and 4–5%, respectively. The hydrophobicity and the acid and alkaline resistance of the film are improved when VETS and HFMA are introduced to co-polymerize with other monomers. Originality/value The fluorine and silicon monomers such as VTES and HFMA and some cheap monomers such as styrene, which are used to prepare the cationic acrylic resin, are seldom reported in the open literature.

A Novel Synthesis of a Magnetic Porous Imprinted Polymer by Polyol Method Coupled with Electrochemical Biomimetic Sensor for the Detection of Folate in Food Samples

The present study reports the development and application of a novel, sensitive, and selective voltammetric sensor for the quantitation of folate or vitamin B9 in foodstuffs. The sensor was made from magnetic molecularly imprinted polymers (MMIPs), which were synthesized by the core–shell method using magnetite nanoparticles obtained by the polyol method. The MMIP-based sensor was used for the selective and specific detection of folate in different food samples. The MMIP material was constructed using magnetic water-dispersible nanomaterial, which was prepared by immersing iron (III) acetylacetonate in tri-ethylene-glycol (TEG) solvent. The magnetic water-dispersible nanomaterial was then subjected to polymerization using allyl alcohol as a functional monomer, ethylene-glycol-dimethacrylate (EGDMA) as a cross-linking agent, and 2,2-Azobisisobutyronitrile (AIBN) as a radical initiator. The proposed magnetic materials were characterized by Brunauer–Emmett–Teller (BET), field emission gun scanning electron microscopy (FEG-SEM), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM) analysis. The quantification of folate was performed by square wave voltammetry under optimized conditions using 15 mg of MMIPs and 85 mg of carbon paste. The modified electrode presented a linear dynamic range (LDR) of 2.0–12 µmol L−1 and a limit of detection (LOD) of 1.0 × 10−7 mol L−1 in 0.1 mol L−1 acetate buffer solution (pH 4.0). The proposed sensor was successfully applied for folate detection in different food samples, where recovery percentages ranging from 93 to 103% were obtained. Finally, the results obtained from the analysis of selectivity showed that the modified biomimetic sensor is highly efficient for folate determination in real food samples. Adsorption tests were used to evaluate and compare the efficiency of the MMIPs and magnetic non-molecularly imprinted polymer (MNIPs)—used as control material, through the application of HPLC as a standard method.

Synthesis of Molecularly Imprinted Polymer Nanoparticles for Removal of Sudan III Dye

Molecularly imprinted polymer (MIP) nanoparticles of Sudan III dye as template were synthesized by using non-covalent approach. The molecularly imprinted polymers were synthesized in a microemulsion contained Sudan III as a template, acrylic acid (AA) as a monomer, 1,4-butanediol dimethacrylate as a cross-linker and 2,2-azo-bisisobutyronitrile (AIBN) as an initiator. The synthesized beads were characterized by TEM and FTIR. The TEM results revealed the nanosize beads of polymers were produced. The efficiency of imprinted and non-imprinted polymers was evaluated by batch binding studies. The results showed that the MIP 3 (0.1: 6: 10, Sudan III: AA: 1,4-butanediol dimethacrylate) was best among all polymers with highest rebinding efficiency. The removal efficiency of selected MIP 3 in the spiked Sudan III dye river water sample was about 80%. This study was conducted to produce nanosized molecularly imprinted polymers by using microemulsion polymerization technique.

Ultrasound-assisted solid phase microextraction-HPLC method based on Fe3O4@SiO2-NH2-molecularly imprinted polymer magnetic nano-sorbent for rapid and efficient extraction of harmaline from Peganum harmala extract

In the present study, a magnetic molecularly imprinted polymer (MMIP) was synthesized for the extraction of harmaline from Peganum harmala by dispersive solid-phase microextraction (DSPME). The MMIP for selective and intelligent extraction of harmaline with excellent functionality and high selectivity was synthesized using the sol-gel method with functionalized superparamagnetic core-shell nanoparticles, ethylene glycol dimethacrylate (EDMA) as a cross-linker, methacrylic acid (MAA) as a functional monomer, and 2,2-azobisisobutyronitrile (AIBN) as a porogen. To study the properties and morphology of the coated polymer, FT-IR spectroscopy, FESEM, TEM images, and VSM were used. The DSPME-HPLC-UV equipment was used to quantify and analyze the data obtained from harmaline extraction. In this research, the efficiency of the synthesized polymer in harmaline extraction was modeled and optimized using the response surface methodology based on central composite design (RSM-CCD). In addition, for modeling the isotherm of harmaline sorption by the MMIP, Langmuir and Freundlich isotherm equations were used. The obtained results showed that the extraction of harmaline with the MMIP was well described with Freundlich isotherm. The results of the validation of the method showed that the measurement of harmaline in the concentration range of 1.0–4000 ng mL−1 followed a linear relationship (R2 = 9986.0). Moreover, the accuracy or repeatability index (% RSD) was determined to be < 10, and the LOQ and LOD values were 0.526 and 0.158 ng mL−1, respectively. The results of this study showed that the DSPME technique by using the synthesized MMIP as an effective sorbent with high efficiency and capacity could be utilized for pre-concentration and extraction of harmaline from real and complex samples.

Experimental Evaluation of the Miniemulsion Polymerization of Vinyl Pivalate: The role of the Main Process Variables

AbstractPoly(vinyl pivalate) (PVPi) nanoparticles obtained via miniemulsion have particular properties useful for several applications. Thus, the present study aims to synthesize and characterize PVPi nanoparticles through the miniemulsion polymerization process, studying the effects of water‐soluble and oil‐soluble initiators, polymerization temperature, and the co‐stabilizer concentration on the final properties of the polymer, nanoparticle size, and conversion. The polymeric nanoparticles are characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance (1H and 13C NMR), thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, dynamic light scattering, and transmission electron microscopy. The miniemulsion polymerization process ensures the formation of a polymeric fluid with high colloidal and thermal stability, with maximum conversions of ≈85% and average particle diameter of 97.2 ± 21.8 nm. The polymeric properties, such as molar mass and glass transition temperature (Tg), are influenced by process variables such as synthesis temperature and the type of initiator. The use of potassium persulfate and 2,2‐azobisisobutyronitrile (AIBN) initiators favors the homogeneous nucleation mechanism, resulting in a decrease in the average particle diameter and in the growth of the chains, result in greater average molar masses and, consequently, greater Tg.

A Novel Molecularly Imprinted Potentiometric Sensor for the Fast Determination of Bisoprolol Fumarate in Biological Samples

AbstractIn this study, molecularly imprinted polymer (MIP) was prepared and used in the preparation of carbon paste electrode (CPE) for the quantification of bisoprolol fumarate (BF) in pure, pharmaceutical formulation and biological fluids. The selective MIP for BF was synthesized from methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross‐linker in dimethyl sulfoxide solution, BF as the template molecule and 2, 2‐azobisisobutyronitrile (AIBN) as the initiator. The non‐imprinted polymer (NIP) was synthesized by the same procedure, but in the absence of the template molecule then incorporated in the paste of the carbon paste electrodes (CPEs). The prepared MIP for BF and its corresponding NIP were well characterized using scanning electron microscopy (SEM), Fourier transform infrared spectrometer, and thermal gravimetric analysis (TGA). The MIP and NIP based CPEs were further used for the determination of BF and the obtained results indicated that the sensor modified by the MIP have much higher recognition power for the BF molecules than the NIP based sensor where the MIP based CPE exhibited a Nernstian response 29.50±0.55 mV decade−1 within a concentration range of 1.0×10−7–1.0×10−2 mol L−1and pH independence in the range 3.50–7.15. The proposed sensor has high selectivity over several possible interfering compounds. The obtained results by the proposed sensor were satisfactory with excellent percentage recovery and relative standard deviation and were comparable with those obtained from HPLC reported method.

A NEW MIP EMBEDDED CRYOGEL FOR SELECTIVE PRE-CONCENTRATION AND REMOVAL OF PROPACHLOR

Propachlor is a pesticide commonly used in the chloroacetanilide herbicide group. Propachlor contamination occurs in groundwater resources and soil sources. Therefore removal and also the determination of trace amounts of propachlor is a very important issue. Molecularly imprinted polymers (MIPS) are preferred for their advantages such as high affinity, strength, and selectivity in pesticide removal and determination. In this study, MIP embedded cryogel was synthesized for selective adsorption and removal of propachlor. MIP synthesis was performed using the template molecule propachlor, functional monomer methacrylic acid, crosslinker ethylene glycol dimethacrylate (EDGMA), solvent hexadecane and 2,2-azo-bis-isobutyronitrile (AIBN) as the initiator. Cryogels are a good alternative for separation and purification because of their advantageous properties such as short diffusion, low pressure and adsorption and elution in a short time. The structure of MIP was determined using scanning electron microscopy (SEM), Elemental analyze and Fourier transform infrared spectroscopy (FT-IR), and the structure of MIP embedded cryogel was determined using scanning electron microscopy (SEM). The highest adsorption capacity for MIP was 5.58 mg g-1 at pH 5. The highest adsorption capacity for MIP embedded cryogel was found to be 14.38 mg g-1. MIP embedded cryogel were used for selective adsorption and desorption of propachlor in environmental samples. The concentration of propachlor in environmental samples was analyzed by high-performance liquid chromatography (HPLC).

Ion-Imprinted Polymer for Selective Separation of Cerium(III) Ions from Rare Earth Mixture

Ion-imprinting polymers (IIPs) materials draw the great recognition because of the powerful selectivity to the desired metal ions. Therefore, the ion-imprinting polymer (Ce-IIP) was prepared by using cerium metal with amidoxime ligand as the complexing agent, in addition ethylene glycol dimethacrylate (EGDMA) and 2,2-azobisisobutyronitrile (AIBN) are crosslinking agent and free radical initiator, respectively. Aqueous HCl was applied to leach the cerium ions from the imprinted polymer for the creation of cavities of template, which is utilized for further cerium ions adsorption with high selectivity. The Ce-IIP was characterized by using ICP-MS, FE-SEM and also solid state analysis by UV-vis NIR spectroscopy. FT-IR study confirmed the complexation of the Ce-IIP was successful. The optimum pH was found to be 6 and the highest adsorption capacity was estimated about 145 mg g-1. Thus, the prepared Ce-IIP gave very good selectivity to cerium ions in the presence of lanthanide ions and also Ce-IIP can be reused 10 times without a substantial loss in adsorption capacity.

Construction of molecularly imprinted nanoparticles by employing ultrasound waves for selective determination of doxepin from human plasma samples: Modeling and optimization.

In this work, molecularly imprinted nanoparticles (MINPs) were applied as selective adsorbent for ultrasound-assisted micro-solid-phase extraction (UAMSPE) of doxepin (DP) from human plasma samples, which was then cleaned up, pre-concentrated and subjected to HPLC. The MINPs were synthesized based on a non-covalent approach by precipitation polymerization utilizing methacrylic acid and styrene as functional monomers, DP as template, ethylene glycol dimethacrylate as cross-linker and 2,2-azobisisobutyronitrile (AIBN) as initiator. The obtained MINPs were characterized by Fourier transform-infrared and field emission scanning electron microscopy. Factors influencing the efficiency of UAMSPE such as sonication time, volume of eluent solvent and amount of sorbent were investigated using a central composite design and the optimal points were identified as 4 min of sonication time, 380 μL of eluent solvent and 30 mg of sorbent. Under optimized conditions, the proposed method has linear responses in the range of 0.2-2000 ng mL-1 , with a satisfactory limit of detection of 0.04 ng mL-1 and limit of quantification of 0.11 ng mL-1 .

Preparation of a novel magnetic Pd(II) ion-imprinted polymer for the fast and selective adsorption of palladium ions from aqueous solutions.

A novel magnetic ion-imprinted polymer with high accessibility to palladium ions was synthesized via co-precipitation polymerization. Accordingly, a ternary complex composed of PdCl2 as an imprinting ion, 8-aminoquinoline (AQ) as a ligand, and 4-vinyl pyridine (4-VP) as a complexing monomer was applied to Fe3O4@SiO2 as magnetic core, followed by precipitation polymerization using 2-hydroxyethyl methacrylate (2-HEMA) as a co-monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinker, and 2,2-azobisisobutyronitrile (AIBN) as an initiator in the presence of 2-methoxyethanol as a solvent. The palladium ions were leached out by a solution containing 50% (v/v) HCl. The synthesized polymer was characterized physically and morphologically using different techniques. In order to assess the conditions required for adsorption, as well as the selectivity and reusability, batch adsorption experiments were carried out. The experiments exhibited that the maximum adsorption capacity was about 65.75mgg-1 at 25°C, while the pH solution and the adsorbent dose were 4 and 1gL-1, respectively. Kinetic studies of experimental data demonstrated that they correspond very much to the pseudo-second-order kinetic model. The development of the Langmuir and Freundlich isothermal models on the equilibrium data proved to correspond well to the Langmuir isotherm model. Interferences studies of the magnetic polymer demonstrated higher affinity and discernment for palladium ions than other co-existing ions in the solutions. Spontaneous (ΔG < 0) and exothermic (ΔH < 0) behavior of the adsorption process is confirmed by thermodynamic studies. In addition, the affinity of the spent polymer has not been dramatically reduced over at least five regeneration cycles.

Ion-imprinted polymer for selective separation of cobalt, cadmium and lead ions from aqueous media

ABSTRACT Ion-imprinting polymers (IIPs) materials draw the great awareness because of the powerful selectivity to the desired metal ions. Thus, the IIPs were prepared by using metals such as Co, Cd and Pb ions with modified curcumin as a functional monomer used for a complexing agent, in addition, ethylene glycol dimethacrylate (EGDMA) and 2,2-azobisisobutyronitrile (AIBN) are crosslinking agent and free radical generator, respectively. Aqueous HCl was used to leach the metal ions from the imprinted polymer for the creation of template cavities, which is further utilized for metal ions adsorption with high selectivity. The IIPs were characterized using the FT-IR, ICP-MS, FE-SEM and also solid state analysis by UV-vis NIR spectroscopy to confirmed the complex formation. The optimum pH was found to be 6 and highest adsorption capacity Q was estimated, 106, 85 and 113 mg g−1 for Co-IIP, Cd-IIP and Pb-IIP, respectively. Thus, the prepared IIPs gave very good selectivity to the metal ions such as Co, Cd and Pb in presence of other metal ions. Regeneration study confirmed the IIPs can be reused 10 times without a substantial loss in adsorption capacity.

Synthesis of Ion-Imprinted Polymer for Selective Separation of Copper(II) from Metal Ions Mixture

Ion imprinted polymers (IIPs) draw great attention in various fields because of powerful selectivity to the target metal ions. Thus, the synthesis of copper-ion imprinted polymer (Cu-IIP) was performed by using copper ion and complexing agent rufigallol with ethylene glycol dimethacrylate (EGDMA) and 2,2-azobisisobutyronitrile (AIBN). Aqueous HCl was used to leach Cu2+ ions from the imprinted polymer for creation of cavities of template, which is utilized for cooper ions adsorption with high selectivity. The IIP were characterized using ICP-MS, FE-SEM and also solid state analysis by UV-visible NIR spectroscopy. FT-IR study confirmed the successful complexation of Cu-IIP. The optimum pH was found to be 6 and highest adsorption capacity was estimated about 112.5 mg g-1. Thus, IIP gave good selectivity to copper ions in presence of other transition metals and also IIP can be regenerated for eight times without a subst-antial loss in adsorption capacity.

Rapid Analysis of Bitertanol in Agro-products Using Molecularly Imprinted Polymers-Surface-Enhanced Raman Spectroscopy

In this work, we first reported molecularly imprinted polymers-surface-enhanced Raman spectroscopy (MIP-SERS) for rapid detection and quantification of bitertanol in cucumber and peaches. In order to remove interference-mitigation effects and avoid template leakage, MIPs were successfully synthesized based on triadimefon molecules as the dummy template, methacrylic acid (MAA) as a functional monomer, trimethylolpropane trimethacrylate (TRIM) as a cross-linker, and 2,2-azobis-isobutyronitrile (AIBN) as an initiator. Static adsorption experiments and Scatchard analysis were then conducted and results showed that the synthesized MIPs could rapidly and selectively adsorb and separate bitertanol from cucumber and peaches due to their predetermined recognition sites. The capacity of MIPs for absorbing bitertanol (∼ 2.21 mg/g) was approximately 1.5 times that of non-imprinted polymers (NIPs) (∼ 1.55 mg/g). Gold nanoparticles (AuNPs) synthesized by sodium citrate reduction method were validated as a suitable SERS colloid for enhancing Raman signals. SERS spectral peaks (760, 985, 1190, and 1279 cm−1) were used to develop quantitative analysis based on partial least-squares regression (PLSR) for bitertanol in cucumber and peaches. The LODs for this method were 0.041 and 0.029 mg/kg in cucumber and peaches, respectively. The entire analysis process required 15 min or less. More importantly, the MIP-SERS system provided not only a rapid, sensitive, and reliable method for bitertanol detection, but also a routine for overcoming the interference-mitigation effects in the SERS technology.

A Facile Synthesis of Cu NPs and Ag NPs Coated by PS with Core-Shell Structure by Precipitation Polymerization

Copper nanoparticles (Cu NPs) coated with polystyrene (PS) (Cu NPs@PS) were prepared by precipitation polymerization. First, Cu NPs were prepared by chemical reduction using cupric acetate as precursor, sodium polyacrylate (PAANa) as stabilizer, and hydrazine hydrate as reducing agent. Then Cu NPs were coated by precipitation polymerization using styrene as monomer, 3-(trimethoxysilyl) propyl acrylate as co-monomer, and 2, 2-azobisisobutyronitrile (AIBN) as initiator. Ultraviolet–visible (UV–vis) spectroscopy and transmission electron microscopy (TEM) results showed that stable composite particles could be synthesized by precipitation polymerization. The amount of PAANa had a significant effect on the size of Cu NPs. The addition of more PAANa resulted in smaller Cu NPs. The spherical Cu NPs became nanowires when increasing the stirring rate from 350 to 700 rpm during precipitation polymerization. Ag NPs@PS with core–shell structure were also prepared by this method, which appears to be universal.

Synthesis and charcterization of diblock copolymers containaing monothio-orthoester functions using raft polymerization

The acyclic and cyclic monothio-orthoester monomers were synthesized by modification of aromatic monomers containing dithioester function in the side chain. Reversible addition-fragmentation chain transfer (RAFT) polymerization was employed for the preparation of polymers containing a dithioester end as macro-chain transfer agents (macro-CTA) using 4-benzyl methyldithiobenzoate (BMDTB) as chain transfer agent (CTA) and 2,2-azobisisobutyronitrile (AIBN) as initiator. A series of diblock copolymers were prepared by RAFT copolymerization of MVDTB, MMMS and MVPOCO, using the different macro-chain transfer agents (macro-CTA) and AIBN as initiator. All polymerizations were carried out at 60 °C for 24 or 30 hours in dry THF. Homopolymers and diblock copolymers are characterized by 1 H NMR, 13 C NMR, IR, SEC, DSC and TGA.

Biomimetic surface modification of polypropylene by surface chain transfer reaction based on mussel-inspired adhesion technology and thiol chemistry

Biomimetic surface modification of polypropylene (PP) is conducted by surface chain transfer reaction based on the mussel-inspired versatile adhesion technology and thiol chemistry, using 2-methacryloyloxyethylphosphorylcholine (MPC) as a hydrophilic monomer mimicking the cell outer membrane structure and 2,2-azobisisobutyronitrile (AIBN) as initiator in ethanol. A layer of polydopamine (PDA) is firstly deposited onto PP surface, which not only offers good interfacial adhesion with PP, but also supplies secondary reaction sites (-NH2) to covalently anchor thiol groups onto PP surface. Then the radical chain transfer to surface-bonded thiol groups and surface re-initiated polymerization of MPC lead to the formation of a thin layer of polymer brush (PMPC) with cell outer membrane mimetic structure on PP surface. X-ray photoelectron spectrophotometer (XPS), atomic force microscopy (AFM) and water contact angle measurements are used to characterize the PP surfaces before and after modification. The protein adsorption and platelet adhesion experiments are also employed to evaluate the interactions of PP surface with biomolecules. The results show that PMPC is successfully grafted onto PP surface. In comparison with bare PP, the resultant PP-PMPC surface exhibits greatly improved protein and platelet resistance performance, which is the contribution of both increased surface hydrophilicity and zwitterionic structure. More importantly, the residue thiol groups on PP-PMPC surface create a new pathway to further functionalize such zwitterion modified PP surface.

Synthesis and application of molecularly imprinted nanoparticles combined ultrasonic assisted for highly selective solid phase extraction trace amount of celecoxib from human plasma samples using design expert (DXB) software

In this work molecular imprinted nanoparticles (MINPs) was synthesized and applied for ultrasonic assisted solid phase extraction of celecoxib (CEL) from human plasma sample following its combination by HPLC–UV. The MINPs were prepared in a non-covalent approach using methacrylic acid as monomer, CEL as template, ethylene glycol dimethacrylate as cross-linker, and 2,2-azobisisobutyronitrile (AIBN) as the initiator of polymerization. pH, volume of rinsing and eluent solvent and amount of sorbent influence on response were investigated using factorial experimental design, while optimum point was achieved and set as 250mg sorbent, pH 7.0, 1.5mL washing solvent and 2mL eluent by analysis of results according to design expert (DX) software. At above specified conditions, CEL in human plasma with complicated matrices with acceptable high recoveries (96%) and RSD% lower than 10% was quantified and estimated.The proposed MISPE-HPLC–UV method has linear responses among peak area and concentrations of CEL in the range of 0.2–2000μgL−1, with regression coefficient of 0.98. The limit of detection (LOD) and quantification (LOQ) based on three and ten times of the noise of HPLC peaks correspond to blank solution were 0.08 and 0.18μgL−1, respectively.

Synthesis of magnetic molecularly imprinted polymers for the selective separation and determination of metronidazole in cosmetic samples.

In this study, novel magnetic molecularly imprinted polymers (MMIPs) were developed as a sorbent for solid-phase extraction (SPE) and used for the selective separation of metronidazole (MNZ) in cosmetics; MNZ was detected by high-performance liquid chromatography (HPLC). First, magnetic Fe3O4 nanoparticles (NPs) were prepared by the co-precipitation of Fe(2+)and Fe(3+) ions in an ammonia solution; then oleic acid (OA) was modified onto the surface of Fe3O4NPs. Finally, the MMIP was prepared by aqueous suspension polymerization, involving the copolymerization of Fe3O4NPs@OA with MNZ as the template molecule, methacrylic acid (MAA) as the functional monomer, ethylene glycol maleic rosinate acrylate (EGMRA) as the cross-linking agent, and 2,2-azobisisobutyronitrile (AIBN) as the initiator. The MMIP materials showed high selective adsorption capacity and fast binding kinetics for MNZ; the maximum adsorption amount of the MMIP to MNZ was 46.7 mg/g. The assay showed a linear range from 0.1 to 20.0 μg/mL for MNZ with the correlation coefficient 0.999. The relative standard deviations (RSD) of intra- and inter-day ranging from 0.71 to 2.45% and from 1.06 to 5.20% were obtained. The MMIP can be applied to the enrichment and determination of MNZ in cosmetic products with the recoveries of spiked toner, powder, and cream cosmetic samples ranging from 90.6 to 104.2, 84.1 to 91.4, and 90.3 to 100.4%, respectively, and the RSD was <3.54%.