The Experts below are selected from a list of 477 Experts worldwide ranked by ideXlab platform
Cesar Ricardo Teixeira Tarley - One of the best experts on this subject based on the ideXlab platform.
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synthesis and evaluation of different adsorbents based on poly methacrylic acid Trimethylolpropane Trimethacrylate and poly vinylimidazole Trimethylolpropane Trimethacrylate for the adsorption of tebuthiuron from aqueous medium
Reactive & Functional Polymers, 2015Co-Authors: Raquel Justo Da Fonseca, Keyller Bastos Borges, Cesar Ricardo Teixeira Tarley, Mariana Gava SegatelliAbstract:Abstract In the present study a new cross-linked copolymer poly(methacrylic acid–Trimethylolpropane Trimethacrylate) (named PMA) and poly(vinylimidazole–Trimethylolpropane Trimethacrylate) (named PVI) was synthesized through precipitation polymerization and applied to the adsorption of tebuthiuron. Adsorbent materials were characterized by using FT-IR, SEM, TGA, textural data, and elemental analysis. Kinetic study showed that the tebuthiuron adsorption was very quick and the equilibrium time was achieved at 20 min for both polymers. Experimental kinetic data for both polymers were very well described by the second-order kinetic model, thus indicating that tebuthiuron adsorption involves chemical adsorption in different binding sites, which could control the reaction rate. Adsorption equilibrium data were better fitted to the dual-site Langmuir–Freundlich model, which recognizes the existence of two kinds of adsorption sites on the polymer surface ascribed to the presence of carboxyl and carbonyl groups from PMA and imidazole ring and carbonyl group from PVI. The maximum adsorption capacities of PMA and PVI were found to be 186.76 and 213.89 mg g − 1 , respectively, which are much higher than other adsorbents.
Per Flodin - One of the best experts on this subject based on the ideXlab platform.
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hydrophilic poly Trimethylolpropane Trimethacrylate co n n methylene bis acrylamide gels
European Polymer Journal, 1993Co-Authors: Andrea Schmid, Per FlodinAbstract:Porous particles were made by suspension copolymerization of Trimethylolpropane Trimethacrylate with N,N′-methylene-bis-acrylamide using ethyl acetate as pore-forming agent. The concentration of N,N′-methylene-bis-acrylamide was varied. The polymers were characterized by scanning electron microscopy, laser diffraction for particle size determination, mercury porosimetry, nitrogen adsorption desorption technique and elemental analysis for nitrogen. The porosity in the swollen state was evaluated by size exclusion chromatography. The analysed amount of nitrogen showed that 82% or more of the N,N′-methylene-bis-acrylamide had polymerized. The pore size distribution became narrower as the amount of N,N′-methylene-bis-acrylamide in the gels increased. In columns packed with water swollen gels, polysaccharide standards were eluted at varying volumes making it possible to construct a calibration curve and to calculate pore size distributions in the wet state. No separation was however obtained with standard proteins.
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mechanical stability of Trimethylolpropane Trimethacrylate based polymers
Journal of Applied Polymer Science, 1992Co-Authors: Andrea Schmid, Maria Walenius, Per FlodinAbstract:Trimethylolpropane Trimethacrylate (TRIM) was homopolymerized and copolymerized with methyl methacrylate (MMA), glycidyl methacrylate (GMA), and acrylamide (AA), respectively, in various solvents and at various temperatures. For comparison, poly(styrene-co-divinyl benzene) [poly(S-co-DVB)] gels were selected. The mechanical stability was measured by compression of the swollen gels. The porogen served as swelling agent. The compression moduli increased with increasing TRIM concentration in the polymerization. The compression moduli of poly(TRIM) could be increased by copolymerization with low concentrations of comonomer. Low polymerization temperature decreased the mechanical strength of poly(TRIM). A good solvent increased the compression modulus. TRIM-based gels were at least as mechanically stable as were poly(S-co-DVB) gels.
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porosity determination of poly Trimethylolpropane Trimethacrylate co methyl methacrylate gels
Macromolecular Chemistry and Physics, 1992Co-Authors: Andrea Schmid, Per FlodinAbstract:In this paper we studied the influence of the copolymerization of Trimethylolpropane Trimethacrylate (TRIM) with methyl methacrylate (MMA) on the pore structure of the resulting gels. TRIM and MMA were suspension-copolymerized with toluene as pore-forming agent. All gels have bimodal pore-size distributions. The size distribution of large pores (r > 50 A) of the solvent-free poly(TRIM-co-MMA) broadens when the TRIM/MMA ratio decreases. The size distribution of small pores (r < 50 A) shows sharp maxima for pores with a radius of 20 A. In the swollen state the separation range for the poly(TRIM-co-MMA) particles of polystyrene standards varies with the TRIM/MMA ratio. The results of the porosity measurements of the swollen gels show good agreement with the results obtained from the dry gels. The porosity of the dry gels was studied with scanning electron microscopy, nitrogen adsorption/desroption and mercury porosimetry. The pore-size distributions of the swollen poly(TRIM-co-MMA) gel particles were calculated from the size-exclusion chromatography (SEC) results.
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synthesis and characterization of copolymers of Trimethylolpropane Trimethacrylate and glycidyl methacrylate in toluene part i
Reactive Polymers, 1992Co-Authors: Maria Walenius, Larsinge Kulin, Per FlodinAbstract:Abstract Suspension copolymerization of glycidyl methacrylate (GMA) and Trimethylolpropane Trimethacrylate (TRIM) was performed with toluene as porogen. To obtain small, spherical beads (10–30 μm in diameter), ethyl hydroxyethyl cellulose combined with homogenization was used to stabilize the suspension. The pore size distribution (PSD) in the dry state shifted towards larger pores whereas the pore volume distribution in the swollen state (obtained from separation of polystyrene standards in toluene by size exclusion chromatography) did not change appreciably as the GMA-to-TRIM ratio increased. The pressure drop at high concentrations of GMA increased as the gel became more elastic. The PSD in the dry and swollen states shifted towards smaller pores (the peak at a pore radius of 20 A became more pronounced in the dry state) as the total monomer to toluene ratio increased.
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hydrophilic gels of poly Trimethylolpropane Trimethacrylate co acrylamide
Reactive Polymers, 1991Co-Authors: A B Schmid, Per FlodinAbstract:Abstract Bulk polymerization of Trimethylolpropane Trimethacrylate (TRIM) and acrylamide resulted in blockpolymers. Ethyl acetate was used as the pore forming agent. The concentration of acrylamide was varied. Characterization of the polymers was done with mercury porosimetry, nitrogen adsorption-desorption technique, elemental analysis of nitrogen, solid state (CP-MAS-DD)13C NMR, pycnometer, and by swelling experiments. The amount of detected nitrogen showed that 85% or more of the added amount of acrylamide had polymerized. The amount of unreacted double bonds decreased as the amount of acrylamide in the polymer increased. The gel, consisting of 27.5 mol % acrylamide, swelled to the same extent in hydrophilic as well as in organic solvents. The BET [1] surface area of poly(TRIM-co-acrylamide) gels increased slightly with the amount of acrylamide (up to 18 mol % acrylamide) in the gel. For polymers with a higher content of acrylamide, the inner surface decreased. The pore size distribution of small pores ( d ≤ 100 A ) showed a decrease in the number of pores when the amount of acrylamide in the gels increased. The differential pore volume of large pores ( d ≥ 100 A ) increased as the amount of acrylamide decreased. The elution volumes for proteins of different molecular weights were determined.
Yongxin She - One of the best experts on this subject based on the ideXlab platform.
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the determination of patulin from food samples using dual dummy molecularly imprinted solid phase extraction coupled with lc ms ms
Journal of Chromatography A, 2019Co-Authors: Minjuan Zhao, Hua Shao, Mengmeng Yan, Zejun Jiang, Jing Wang, A Abd M Elaty, Ahmet Hacimuftuoglu, Feiyan Yan, Yanli Wang, Yongxin SheAbstract:A molecularly imprinted polymer (MIP) with specific adsorption for patulin was successfully polymerized by precipitation polymerization using 2-oxindole (2-oxin) and 6-hydroxynicotinic acid (6-HNA) as dummy template molecules, methylacrylic acid (MAA) as a functional monomer, Trimethylolpropane Trimethacrylate (TRIM) as a crosslinker, 2,2-azobis-(2-methylpropionitrile) (AIBN) as a initiator, and methanol as a porogen solvent. The molecularly imprinted solid phase extraction (MI-SPE) column was prepared using the polymer as a sorbent and applied for the selective extraction of patulin from real samples. The results showed that the MI-SPE method had high selectivity and specific adsorption towards patulin with mean recoveries ranged between 81.3% and 106.3% and a relative standard deviation (RSD) 0.998. The limits of detection (LODs, S/N = 3) were 0.05–0.2 ng g−1, and the limits of quantification (LOQs, S/N = 10) were 0.2–0.5 ng g−1. The developed method showed a better purification and higher patulin recovery for real samples than the quick, easy, cheap, effective, rugged, safe “QuEChERS” method.
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selective solid phase extraction based on molecularly imprinted technology for the simultaneous determination of 20 triazole pesticides in cucumber samples using high performance liquid chromatography tandem mass spectrometry
Journal of Chromatography B, 2017Co-Authors: Fengnian Zhao, Hua Shao, Yongxin She, Chao Zhang, Xiaolin Cao, Shanshan Wang, Lufei Zheng, Maojun Jin, Fen Jin, Jing WangAbstract:A selective analytical method for the simultaneous determination of 20 triazole fungicides and plant growth regulators in cucumber samples was developed using solid-phase extraction with specific molecularly imprinted polymers (MIPs) as adsorbents. The MIPs were successfully prepared by precipitation polymerization using triadimefon as the template molecule, methacrylic acid as the functional monomer, Trimethylolpropane Trimethacrylate as the crosslinker, and acetonitrile as the porogen. The performance and recognition mechanism for both the MIPs and non-molecularly imprinted polymers were evaluated using adsorption isotherms and adsorption kinetics. Liquid chromatography-tandem quadrupole mass spectrometry was used to identify and quantify the target analytes. The solid-phase extraction using the MIPs was rapid, convenient, and efficient for extraction and enrichment of the 20 triazole pesticides from cucumber samples. The recoveries obtained at three concentration levels (1, 2, and 10μgL-1) ranged from 82.3% to 117.6% with relative standard deviations of less than 11.8% (n=5) for all analytes. The limits of detection for the 20 triazole pesticides were all less than 0.4μgL-1, and were sufficient to meet international standards.
Keyller Bastos Borges - One of the best experts on this subject based on the ideXlab platform.
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pipette tip solid phase extraction using poly 1 vinylimidazole co Trimethylolpropane Trimethacrylate as a new molecularly imprinted polymer in the determination of avermectins and milbemycins in fruit juice and water samples
Food Chemistry, 2018Co-Authors: Roseane Andrade Teixeira, Diego Hernando ângulo Flores, Ricky Cassio Santos Da Silva, Flavia Viana Avelar Dutra, Keyller Bastos BorgesAbstract:Abstract A simple HPLC method was developed for the determination of abamectin (ABA), eprinomectin (EPR), and moxidectin (MOX). Pipette-tip molecularly imprinted polymer solid-phase extraction (PT–MIP–SPE) using poly(1-vinylimidazole-co-Trimethylolpropane Trimethacrylate) as a selective adsorbent material was studied in detail, including the washing solvent, type and volume of eluent, pH, quantity of adsorbent material and sample volume. The performance criteria for linearity, sensitivity, precision, accuracy, recovery, robustness and stability have been assessed and were within the recommended guidelines. The mean extraction recoveries/relative standard deviation for ABA 1b, EPR, ABA 1a and MOX were 98.77 ± 3.82%, 88.19 ± 2.57%, 110.54 ± 1.52% and 100.42 ± 0.59%, respectively. Finally, the results proved that PT–MIP–SPE coupled to HPLC–UV is an economical, simple and easy-to-perform technique, and presented a high potential for extraction of macrocyclic lactones in mineral water and grape and juice samples.
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synthesis and evaluation of different adsorbents based on poly methacrylic acid Trimethylolpropane Trimethacrylate and poly vinylimidazole Trimethylolpropane Trimethacrylate for the adsorption of tebuthiuron from aqueous medium
Reactive & Functional Polymers, 2015Co-Authors: Raquel Justo Da Fonseca, Keyller Bastos Borges, Cesar Ricardo Teixeira Tarley, Mariana Gava SegatelliAbstract:Abstract In the present study a new cross-linked copolymer poly(methacrylic acid–Trimethylolpropane Trimethacrylate) (named PMA) and poly(vinylimidazole–Trimethylolpropane Trimethacrylate) (named PVI) was synthesized through precipitation polymerization and applied to the adsorption of tebuthiuron. Adsorbent materials were characterized by using FT-IR, SEM, TGA, textural data, and elemental analysis. Kinetic study showed that the tebuthiuron adsorption was very quick and the equilibrium time was achieved at 20 min for both polymers. Experimental kinetic data for both polymers were very well described by the second-order kinetic model, thus indicating that tebuthiuron adsorption involves chemical adsorption in different binding sites, which could control the reaction rate. Adsorption equilibrium data were better fitted to the dual-site Langmuir–Freundlich model, which recognizes the existence of two kinds of adsorption sites on the polymer surface ascribed to the presence of carboxyl and carbonyl groups from PMA and imidazole ring and carbonyl group from PVI. The maximum adsorption capacities of PMA and PVI were found to be 186.76 and 213.89 mg g − 1 , respectively, which are much higher than other adsorbents.
Shuo Wang - One of the best experts on this subject based on the ideXlab platform.
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molecularly imprinted solid phase extraction coupled to high performance liquid chromatography for determination of trace dichlorvos residues in vegetables
Food Chemistry, 2010Co-Authors: Guozhen Fang, Shuo WangAbstract:Abstract In this paper, we prepared a highly selective imprinted polymer by a room temperature ionic liquid-mediated bulk polymerization technique, using dichlorvos as the template, methacrylic acid as the functional monomers, and Trimethylolpropane Trimethacrylate as the cross-linker. This functionalized material was characterized by FT-IR, static and kinetic adsorption experiments, and the results showed that this imprinted sorbent exhibited good recognition and selective ability, and offered fast kinetics for the adsorption and desorption of dichlorvos. Using the prepared material as a solid phase extraction sorbent, a novel sample pre-treatment technique that can be coupled to high-performance liquid chromatography (HPLC) had been developed for determination of trace dichlorvos residues in foods. Under the selected experimental condition, the detection limit ( S / N = 3) of dichlorvos was 94.8 ng L −1 , and the peak area precision (RSD) for five replicate detections of 10 μg L −1 dichlorvos was 4.41%. The blank samples of cucumber and lettuce spiked with dichlorvos at 0.005 and 0.02 μg g −1 levels were determined with recoveries ranging from 82.1% to 94.0%.
