Polystyrene-divinylbenzene Copolymer Research Articles

Selective Recovery of Anthocyanins and Hydroxycinnamates from a Byproduct of Citrus Processing

The adsorption-desorption performances of commercial resins (two polystyrene-divinylbenzene copolymers and one methacrylic) were tested in column studies for the selective recovery of anthocyanins and hydroxycinnamates from pigmented pulp wash (PW), a byproduct of blood orange juice processing. Methanol, ethanol, and their mixtures with different percentages of water as eluents were tested in order to investigate the selective desorption of these natural antioxidants with the goal of minimizing the presence of other compounds, mostly flavanones and limonoids, in the concentrated eluates. The results indicated that polystyrene-divinylbenzene resins were able to adsorb a major amount of anthocyanins and hydroxycinnamates and to desorb them in more-concentrated fractions. No selectivity was observed using pure methanol and ethanol which resulted in concentrates with no further separation of components from the starting raw PW. The ethanol/water concentrates showed higher yields than the fractions attained using methanol/water; however, a lower selectivity toward anthocyanin pigments was observed. The best performing resin, EXA-118, together with the mixture methanol/water 50:50 (v/v) as best eluent, appears to be the most suitable system to obtain highly concentrated extracts. Thus, it was chosen to perform a larger experiment, to analyze the selectivity of the removal upon an increase in elution volume.

Adsorption of pesticides on porous polymeric adsorbents

The adsorption of herbicides alachlor, amitrole, trifluralin and prometryn on porous polymeric adsorbents has been studied. Two adsorbent resins were investigated, the highly hydrophobic Amberlite XAD-4 (polystyrene–divinylbenzene copolymer) and the functionalized more hydrophilic XAD-7 (nonionic aliphatic acrylic polymer). Equilibrium adsorption experiments using buffered aqueous solutions were conducted to estimate the types of isotherms and their parameters. The effect of chemical composition and structure of the herbicides, was investigated. The pH range studied was 3–6.5, the temperature range was 288–303 K and the ionic strength was maintained at 0.01 M. Adsorption isotherms seemed generally to approach the Langmuir or Freundlich isotherm model and can be characterized by temperature and pH dependent apparent adsorption equilibrium constants, characteristic of the adsorbent–adsorbate system. By studying the dependence of temperature of this adsorption constant, heats of adsorption have been estimated from van’t Hoff law. In the case of trifluralin and prometryn adsorption on both resins and amitrole adsorption on XAD-4 resin, the heats of adsorption were negative (8.1–33.6 kcal/mol). On the contrary, in alachlor adsorption on both resins and amitrole adsorption on XAD-7 resin, the estimated heats of adsorption were positive.

Thermally denaturing high-performance liquid chromatography analysis of primase activity

Prokaryotic primase, a DNA-dependent RNA polymerase, is a target of interest for the development of novel antibiotics. A new assay was developed to evaluate the inhibition of primase activity while avoiding the limitations of existing assays that require the incorporation of radiolabeled nucleotides into the growing primer followed by electrophoretic separation and autoradiography or scintillation counting. These existing technologies are either time consuming or unable to give detailed information on the kinetics, size, and nature of the primers synthesized. To address these issues in a nonradioactive manner, a thermally denaturing high-performance liquid chromatography (HPLC) assay was developed that was able to (1) measure the two modes of primase activity (de novo and overlong primer synthesis), (2) quantitate de novo primer synthesis kinetics yielding a rate constant of 0.00251 s −1, and (3) determine that dNTPs inhibited primase activity with an IC50 of 9.5 μM. In addition, the differential elution properties of short DNA and RNA oligonucleotides on an alkylated nonporous polystyrene–divinylbenzene copolymer microsphere bead column were determined. The thermally denaturing HPLC assay provides rapid quantitative analysis of primase function and qualitative analysis of activity with regard to the nature of the primers synthesized.

Polystyrene monolithic column functionalized with copper–iminodiacetate complex as a stationary phase for open tubular capillary electrochromatography

Polystyrene–divinylbenzene copolymer functionalized with copper–iminodiacetate complex was prepared in situ for the capillary electrochromatographic separation of amino acids and oligopeptides. The steps included silanization of the fused-silica capillary column, functionalization, polymerization, hydrolysis and complexation. For having a homogeneous polymerization system in the selected porogen, the functional monomer was obtained from the reaction of 4-vinylbenzyl chloride and diethyl iminodiacetate. Scanning electron microscopy showed that the polymeric monolith column was an open tubular column with a thickness of 0.3 μm. Various modes of hydrolysis were investigated via the electroosmatic flow measurement to find the optimization condition prior to introducing the copper ion. The influence of pH, composition and concentration of mobile phase as well as the organic modifier were investigated. Judging from our results, the recognition performance of the prepared stationary phase might be integrated from the mechanisms of ligand exchange, electrophoretic mobility, hydrophobic interaction, and hydrogen bonding.

Suspension Ring-Opening Metathesis Polymerization: The Preparation of Norbornene-Based Resins for Application in Organic Synthesis

A series of norbornene-based resin beads were obtained by aqueous suspension ring-opening metathesis polymerization (ROMP) and used as polymeric supports for organic synthesis. These resins were prepared from norbornene, norborn-2-ene-5-methanol, and cross-linkers such as bis(norborn-2-ene-5-methoxy)alkanes, di(norborn-2-ene-5-methyl)ether, and 1,3-di(norborn-2-ene-5-methoxy)benzene. The resulting unsaturated ROMP (U-ROMP) resins containing olefin repeat units were chemically modified using hydrogenation, hydrofluorination, chlorination, and bromination reactions to produce saturated ROMP resins with different chemical and physical properties. The hydrogenated ROMP (H-ROMP) resin was found to be highly resistant to acidic, basic, Lewis acid, and Birch reduction conditions and was assessed as a polymeric support in a series of solid-phase synthetic applications. The H-ROMP resin was found to have superior performance compared to polystyrene-divinylbenzene (PS-DVB) copolymers in aromatic nitration and acylation reactions. In a conventional five-step solid-phase synthesis of a hydantoin, similar results were obtained for both the H-ROMP and PS-DVB resins. The U-ROMP resin was also shown to be effective in the solid-phase syntheses of benzimidazoles and benzimidazolones.

Liquid chromatography and differential scanning calorimetry studies on the states of water in polystyrene–divinylbenzene copolymer gels

The thermal phase transition behavior of water incorporated in crosslinked polystyrene–divinylbenzene copolymer (PS–DVB) gel packings for liquid chromatography was investigated by differential scanning calorimetry. Free or bulk water, freezable bound or intermediate water, and nonfreezing water were observed for TSKgel Styrene-250 samples, while only free water and nonfreezing water were observed for TSKgel Styrene-60 samples. Freezable bound water and nonfreezing water in these gel samples were considered to be water confined in pores of the polymer gels. A liquid chromatographic method for determination of the amounts of stationary phase water was applied to the characterization of water in the PS–DVB beads in the columns and it was found out that any water in the PS–DVB gels did not function as the stationary phase contrary to the water sorbed in hydrophilic polymer gels; not only freezable bound water but also nonfreezing water in hydrophobic PS–DVB gels are similar to bulk water with respect to the affinity to the solute compounds.

A column system for the selective extraction of U(VI) and Th(IV) using a new chelating sorbent

A new method has been developed using (bis-3,4-dihydroxy benzyl) p-phenylene diamine functionalized to XAD-16 (a polystyrene divinyl benzene copolymer) matrix, to preconcentrate mainly U(VI) and Th(IV) from synthetic and real samples. The developed method is free from matrix interference due to alkali and alkaline metal ions and preconcentrates the actinides with a high degree of selectivity, with consistent trace recoveries. The new chelating resin provides dramatic improvement in metal exchange rate, with half value saturation time ( t 1/2) of less than 1.6 min. The developed method was superior in its metal loading capacity for U(VI) and Th(IV), with values of 0.666 and 0.664 mmol g −1, respectively. Various physio-chemical properties like effect of solution pH, kinetic studies, resin loading capacity, sample breakthrough volume, matrix effects etc., on metal ion sorption to sorbent phase, were studied using both batch and column method. The new chelatogen was applied to extract U(VI) from near neutral real water samples. Preconcentration and separation of metal ions were possible through pH variation and also by varying the eluant concentration. A high preconcentration factor value of 350 with a lower limit of detection of 20 and 30 ng cm −3 was obtained for U(VI) and Th(IV), respectively. The practical applicability of the developed resin was examined using synthetic and real samples such as sea/well water samples. The method provides low relative standard deviation values of <3.5% for all analytical measurements, reflecting on the reproducibility and accuracy of the developed method. The new resin is quite durable with recycling time >35 cycles, without any major change in its quantitative metal uptake nature.

Application of the solid-phase extraction procedure on chromatographic mini column filled with Diaion HP-20 for determination of copper, cobalt, cadmium, iron and manganese in textile products and textile wastewaters

The concentration of copper (II), cobalt(II), cadmium(II), iron(III) and manganese(II) of some textile materials produced in Kayseri, Turkey, and textile wastewater samples from Kayseri were determined by atomic absorption spectrometry after solid-phase extraction of these ions on Diaion HP-20 adsorption resin which is polystyrene divinylbenzene copolymer. The influences of the matrix of components on the recoveries of analyte ions were also investigated. The levels of analyte ions in the investigated textile samples were found below the limit values given by Oeko-Tex Standard 100.

Analysis of benzo[a]pyrene diol epoxide-DNA adducts by capillary zone electrophoresis- electrospray ionization-mass spectrometry in conjunction with sample stacking.

Benzo[a]pyrene diol epoxide (BPDE) was reacted in vitro with (2'-deoxy)nucleotides and with calf thymus DNA. The modified DNA was enzymatically hydrolyzed to the 5'-monophosphate nucleotides using deoxyribonuclease I (DNA-ase I), nuclease P1 and snake venom phosphodiesterase (SVP). Most of the unmodified nucleotides were removed using solid phase extraction (SPE) in a polystyrene divinylbenzene copolymer. Three adducts could be detected and identified using capillary zone electrophoresis(negative)-ion electrospray ionization-mass spectrometry (CZE-(-)-ESI-MS) in conjunction with sample stacking. This way, not only a BPDE-dGMP adduct [(M-H)(-) at m/z 648], a well-known nucleotide adduct, could be retrieved, but also a BPDE-dAMP [(M-H)(-) at m/z 632] and a BPDE-dCMP adduct [(M-H)(-) at m/z 608] could be detected for the first time. The presence of the prominent ion at m/z 195 (the deoxyribose-phosphate ion) in the three low-energy collision-activated decomposition (CAD) spectra indicated that the adducts were formed through base-alkylation. CZE-positive ion ESI-MS/MS experiments were performed to obtain further information on base-alkylation. The absence of the loss of NH(3) from the nucleobase in each CAD spectrum points to an alkylated exocyclic NH(2) position of the nucleobase. So, the three adducts could be identified as BPDE-N(2)-dGMP, BPDE-N(6)-dAMP and BPDE-N(4)-dCMP using CZE-ESI-MS and CZE-ESI-MS/MS.

SPOCC-194, a new high functional group density PEG-based resin for solid-phase organic synthesis.

A novel polymer matrix for solid-phase synthesis, SPOCC(194) resin (1), was designed featuring a backbone of homogeneous tetraethylene glycol (TEG(194)) macromonomer linked by quaternary carbon junctions and terminating in primary alcohol functionality. Beaded SPOCC(194) resin was effectively prepared by suspension polymerization of oxetanylated TEG macromonomer 5 in stirred silicon oil. Mechanically stable and inert to a diverse range of reaction conditions, SPOCC(194) possessed a high hydroxyl group loading (0.9-1.2 mmol/g) for substrate attachment and swelled effectively ( approximately 2-4 mL/g) in a variety of organic and aqueous solvents. Developed for solid-phase synthesis at high reactant concentrations for driving organic and aqueous reactions to completion, SPOCC(194) exhibited high functional group density (mmol/mL) similar to that of low-loaded aminomethylated polystyrene-divinylbenzene copolymer (PS-1%DVB) yet significantly higher than that of PEGA(1900), SPOCC(1500), and TentaGel S. High-resolution MAS NMR spectra of Fmoc-derivatized SPOCC(194) indicate that monitoring of functional group transformation is possible. Moreover, by employment of a nonaromatic resin-linker combination, electrophilic chemistry, such as Lewis acid catalyzed glycosylation and Friedel-Crafts acylation, was selectively performed on substrate bound to SPOCC(194) resin. Such properties make SPOCC(194) resin a promising new polymer matrix for the support-bound construction of small organic molecules by parallel and combinatorial synthesis and the scavenging of solution-phase reactants or byproducts.

Determination of Naphthalenesulfonate Isomers in Industrial Effluents and River Water by Solid‐Phase Extraction and Capillary Zone Electrophoresis

AbstractThis work presents a method to separate polar naphthalenesulfonate (NS) isomers by capillary zone electrophoresis (CZE) with ultraviolet detection in industrial effluents and river water samples. The method involves extraction of samples by a polystyrene‐divinylbenzene copolymer (PS‐DVB) solid‐phase extraction (SPE) cartridge. The most effective CZE separation conditions were obtained in 20 mM borate buffer with 30% acetonitrile at pH 9.0 and 30 °C. The method proposed herein provides a high precision and sensitivity for NS isomers, to quantitation at ≤ 1.0 μg/L in 200 mL of the water samples. Recovery of the NS isomers in spiked water samples ranged from 73% to 87% while RSD ranging from 5.6 to 9.7%. The analysis of industrial effluents and river water samples was performed and naphthalene‐2‐sulfonate was found as a major pollutant. The difficulties in quantitating and identifying analytes in complex environmental samples can be resolved by using an internal standard response factor to calculate concentrations and relative migration times for peak confirmation.

Sulfoacylated macro-porous polystyrene-divinylbenzene low-capacity cation exchanger selective for amino acids.

A low-capacity cation-exchange column was newly developed for the separation of amino acids. A highly cross-linked macro-porous polystyrene-divinylbenzene co-polymer was functionalized by a sulfoacylation reaction. The exchange capacity was controllable at the acylation step. The capacity between 55 and 60 micromol/column was adequate for the practical separations in acceptable retention times. The 5-microm base polymers having average pore diameters smaller than 3 nm gave satisfactory results, and those having 1.5-nm pore was most favorable. Several isocratic elution conditions at different pH values adjusted by phosphate buffer of mM order with or without acetonitrile could provide good separations for individual classes of amino acids, i.e., acidic, neutral, hydrophobic, and basic groups. The results provided fundamental data for constructing gradient elution systems required for the simultaneous separation of protein amino acids.

Synthesis and characterization of a new resin functionalized with 2-naphthol-3,6-disulfonic acid and its application for the speciation of chromium in natural water

A polystyrene divinyl benzene (8%) copolymer has been functionalized by coupling it through NN group with 2-naphthol-3,6-disulfonic acid (NDSA). The resulting resin has been characterized by elemental analysis, thermogravimetric analysis and infrared spectra. The hydrogen ion, water regain and metal ion capacities of the resin have been determined. Two forms of chromium show different exchange capacities at different pH values, viz. Cr(III) selectively retained at pH 6.5 whereas Cr(VI) retained at pH 1.5. Hence complete separation of the two forms of chromium is possible. The kinetic studies show that the exchange of Cr(III) and Cr(VI) follows second-order kinetics. The metal ion concentration was measured by flame atomic absorption spectrometry. The method has been successfully applied for the speciation of chromium in natural water samples.

Adsorption of organic pollutants from effluents of a Kraft pulp mill on activated carbon and polymer resin

Adsorption of acidic bleach plant effluent on activated carbon and a polymer resin (polystyrene divinylbenzene copolymer) was studied at ambient conditions. The adsorption isotherms can be well described using the Freundlich equation. The pH of the wastewater solution influences significantly the adsorption capacity of activated carbon. The maximum adsorption capacity for total organic carbon (TOC) on both activated carbon and the selected resin was obtained at pH 2. The resin is more effective than activated carbon in color removal from pulp mill effluents. The TOC adsorption capacity of the resin can be fully restored by washing with sodium hydroxide solution. Other factors influencing the adsorption capacity are also discussed.

Removal of amino acids from water by adsorption on polystyrene resins

The adsorption of eight amino acids, L-asparagine, D,L-threonine, L-lysine, L-leucine D,L-methionine, L-tyrosine, L-phenylalanine and D,L-tryptophan, on the non-polar macroporous adsorbents Amberlite XAD-2 and XAD-4 (polystyrene–divinylbenzene copolymers) was studied. Equilibrium adsorption experiments were conducted to estimate the types of isotherm and their parameters. The effect the chemical composition and structure of the amino acids on the efficiency of adsorption was evaluated. The influence of pH and ionic strength was also studied. The data of adsorption isotherms of the examined amino acids seemed generally to approach the Freundlich isotherm model. Tryptophan isotherm adsorption data could match in some cases the Langmuir model. The majority of the adsorption isotherms were almost linear. In terms of adsorbed amino acid on both resin surfaces, the amino acids can be ranked thus: D,L-tryptophan > L-phenylalanine > D,L-methionine, L-tyrosine > L-leucine > L-lysine > D,L-threonine > L-asparagine. In low pH solution, adsorption was generally higher than that at intermediate and high pH values. Generally, as the ionic strength increases, the adsorption of the amino acids increases. © 2001 Society of Chemical Industry

Calcium Carbonate Deposition on Cellulose

Cellulose powder was found to be a substrate favoring the deposition of calcite crystals from stable supersaturated solutions at pH 8.50 and at 25°C. Kinetic analysis of the initial rates showed that they were proportional with the relative supersaturation with respect to calcite. Analysis of the dependence of the induction periods on the initial solution conditions showed that the number of ions forming the critical nucleus was 5. The second-order dependence of the rate of precipitation of calcite on cellulose on the solution supersaturation suggested a surface controlled mechanism. The surface energy of the calcite nuclei growing on cellulose was calculated to be 46 mJ m−2 from the dependence of the induction time on the solution supersaturation. The overgrowth of calcite on cellulose was done selectively on the macromolecules possibly through active sites formation at ionizable functional groups (-OH). The nucleating capability of cellulose was found to be comparable with that of sulfonated polystyrene and significantly lower in comparison with sulfonated polystyrene divinyl benzene copolymer on which vaterite was formed. This fact together with the selective growth of the most stable calcite suggested that stereochemical factors are very important in determining both the kinetics and the nature of the polymorph formed.

The Use of Palmitoyl Hydroxyquinoline-Functionalized Amberlite XAD-2 Copolymer Resin for the Preconcentration and Speciation Analysis of Gallium(III)

Gallium (Ga) is a valuable element in the electronics industry for manufacturing semiconductors and lasers. The processing of bauxite ores for the recovery of Ga, as well as high-level purification of the raw Ga product as required by electronic applications, necessitate effective speciation analysis of this element. For differentiating chemically important Ga(III) species, the Amberlite XAD-2 polystyrene-divinylbenzene copolymer was chloromethylated using AlCl3 as a catalyst, and later, 5-palmitoyl-8-hydroxyquinoline was covalently bound to this chloromethylated product via Friedel-Crafts reaction, resulting in the synthesis of a Ga-specific resin (Amberlite XAD-2-P·Ox). This resin has been shown to preconcentrate Ga selectively from basic aluminate solutions. The investigation of the effect of acidity on Ga recovery revealed that Ga was quantitatively retained on the resin between pH 3 and 7. The sorbed Ga could be eluted with 1 M HCl. A 100-mL volume of 2 ppm Ga showed 100% uptake by 10 g of resin using a flow rate of 1 mL/min. Here, all simple inorganic salts of Ga (e.g., Ga(III) nitrate, chloride, perchlorate), as well as the aquated Ga3+ (hexaaqua-complex) species, exhibit quantitative retention. On the other hand, oxalate-, tartrate-, citrate-, acetylacetonate, and EDTA complexes of gallium(III) were not retained by the resin under identical conditions. Thus, the synthesized chelating cation-exchanger showed selective affinity to simple inorganic Ga(III) salts, in a way acting as an ion-selective electrode for Ga3+ while excluding coordinatively saturated stable Ga-complexes. The developed ion-exchange procedure was used to separate gallium from arsenate in a commercial gallium arsenide sample, followed by Ga determination without interference.

Preparation and Properties of a New Chelating Resin Containing Sulfur and Nitrogen Donor Atoms

AbstractA novel chelating resin was obtained by incorporating 2‐mercaptoethylamine into polystyrene divinylbenzene copolymer. Conversion of functional groups of the resin was confirmed by IR spectra, elemental analysis, hydrogen capacity, and protonation constants. The functionality of the resin is 0.45 mmol g−1. The water regain as a function of pH was determined. The coordination behavior of the resin was investigated by IR, EPR and potentiometry. Effects of pH on adsorption of metal ions to the resin, both at large excess and limited amount of metal ions were examined. The resin exhibits exceptionally high affinity for soft metal ions, even in highly acidic aqueous media. EPR measurements at different copper loading were made. The results showed that the copper(II)‐resin complex might be distorted tetragonal. Protonation constants and stability constants of the resin were determined at 25 °C and ionic strength of 0.5 M KCl solution. The selectivity of the resin toward metal ions decreased in the order: Au(III) &gt; Pt(IV) &gt; Ag(I) &gt; Pd(II) &gt; Hg(II) &gt; Fe(III) &gt; Cu(II) &gt; Zn(II) &gt; Cd(II) &gt; Ni(II) ≡ Co(II). Metal ion coordination occurs primarily at the nitrogen and sulfur donor atoms, but the polymeric backbone also makes significant contribution to metal binding. The resin demonstrated high promise for the collection and analysis of noble metal ions, especially from complex matrix samples.

Stationary-Phase Complexation of Crown Ethers with Polyammonium Ions Chemically Bonded on Polymer Resin

The apparent comlexation of crown ethers with polyammonium ions chemically bonded on polystyrene-divinylbenzene copolymer resin has been chromatographically studied in methanol and acetonitrile. The retention of crown ethers with chemically bonded ammonium ion resins is affected by the nature of the counteranions; the retention is enhanced with large and poorly solvated counteranions, but is reduced with small and well solvated counteranions. In the present study, the retention mechanisms are discussed based on the retention data obtained by changing various factors, such as the crown cavity sizes, the structures of the polyammonium ions, counteranions, and the molar ratios of mixed counteranions in the stationary phase. The complexation and ion-pair formation equilibria play important roles in determining the over-all retention of crown ethers.

Determination of Polar Organic Pollutants in Aqueous Samples of Former Ammunition Sites in Lower Saxony by Means of HPLC/Photodiode Array Detection (HPLC/PDA) and Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR)

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