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Drug-resin complexes usually form in the aqueous phase. For poorly water-soluble drugs, low drug loading limits the use of resin in drug formulation. In this study, we used a new method to prepare azithromycin resinates, improving the drug loading rate, shortening the preparation time and simplifying the process. We used hydro-alcoholic solution as the drug loading solvent and the ion exchange resin as the carrier, and this method enabled the resin to adsorb both the retardant and the drug. The sustained release effect of retardant Eudragit RL, RS100 was analyzed. Drug loading efficiency, release profiles, morphology, physicochemical characterization and pharmacokinetic study were assessed. Preparation of drug resinate by batch method resulted in 14% higher drug loading of azithromycin and 3.5 h shorter loading time as compared to pure water for hydroalcoholic solution as drug loading solvent. Raman mappings demonstrated that the retardant with higher molecular weight was more likely to adsorb to the outer layer of the resin compared to the drug. The in vitro release and in vivo pharmacokinetic study of azithromycin resinates showed a sustained release profile with few gastrointestinal adverse effects. Therefore, the addition of ethanol not only improved the efficiency of drug loading but also showed sustained-release effect with one-pot preparation of azithromycin resinates., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Anaerobically-treated palm oil mill effluent (POME) still has unacceptable properties for water recycling and reuse, with an unpleasant appearance due to the brownish color caused by tannins and phenolic compounds. This study proposes an approach for treating anaerobically-treated POME for water recycling by combining organic precipitation, electrocoagulation (EC), and ion-exchange resin, followed by reverse osmosis (RO) membrane filtration in series. The results indicated that the organic precipitation enhanced the efficiency of EC treatment in reducing the concentrations of tannins, color, and chemical oxygen demand (COD) of the anaerobically-treated POME effluent, with reductions of 95.73%, 96.31%, and 93.96% for tannin, color, and COD, respectively. Moreover, organic precipitation affected the effectiveness of Ca 2+ and Mg 2+ ion removal using ion exchange resin and RO membrane filtration. Without prior organic precipitation, the ion-exchange resin process required a longer contact time, and the RO membrane filtration treatment was hardly effective in removing total dissolved solids (TDS). The combined process gave a water quality that meets the criteria set by the Thailand Ministry of Industry for industrial boiler use (COD 88 mg/L, TDS <0.001 mg/L, water hardness <5 mg-CaCO 3 /L, and pH 6.9)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Improved measurement and analysis technologies are needed for investigating nanoparticle generation characteristics in sewage treatment plants. Single-particle inductively coupled plasma-mass spectrometry (spICP-MS) can be used to analyze metal nanoparticle characteristics. However, during spICP-MS analysis of environmental samples, high concentrations of ionic materials obscure the signals of particulate materials by increasing background signals. This can increase the threshold value for separating background and particle signals and increase the background-equivalent diameter (BED). In this study, particle size distributions in influent and effluent collected from sewage treatment plants were investigated using an improved spICP-MS method combining spICP-MS with ion-exchange resin (IER) column pretreatment. The ion removal effect of the IER column was first examined using a synthetic mixture of Ag nanoparticles (AgNPs) and ions. The method was then applied to wastewater from six different sewage treatment plants using an optimal IER packing of 5 g. The ion removal efficiency for samples containing a proper mixture of AgNPs and Ag ions was 99.98%, and the BED significantly decreased from 73.0 ± 1.0 to 6.1 ± 0.3 nm. Particle size distributions measured in the treatment plant influent and effluent ranged from 28.5 nm (Co) to 220.3 nm (Mg) and from 26.8 nm (Co) to 291.8 nm (Mg), respectively. spICP-MS/IER enabled the detection of smaller particles by removing ions from the sample and significantly decreasing the size detection limit. The results of this study offer a reference for developing predictive models for removing metal nanoparticles during sewage/wastewater treatment., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Driven by climate change and human activity, Sargassum blooming rates have intensified, producing copious amount of the invasive, pelagic seaweed across the Caribbean and Latin America. Battery recycling and lead-smelter wastes have heavily polluted the environment and resulted in acute lead poisoning in children through widespread heavy metal contamination particular in East Trinidad. Our study details a comprehensive investigation into the use of Sargassum (S. natans), as a potential resource-circular feedstock for the synthesis of calcium alginate beads utilized in heavy metal adsorption, both in batch and column experiments. Here, ionic cross-linking of extracted sodium alginate with calcium chloride was utilized to create functional ion-exchange beads. Given the low quality of alginates extracted from Sargassum which produce poor morphological beads, composite beads in conjunction with graphene oxide and acrylamide were used to improve fabrication. Stand-alone calcium alginate beads exhibited superior Pb 2+ adsorption, with a capacity of 213 mg g -1 at 20 °C and pH 3.5, surpassing composite and commercial resins. Additives like acrylamide and graphene oxide in composite alginate resins led to a 21-40% decrease in Pb 2+ adsorption due to reduced active sites. Column operations confirmed Alginate systems' practicality, with 20-24% longer operating times, 15 times lower adsorbent mass on scale-up and 206% smaller column diameters compared to commercial counterparts. Ultimately, this study advocates for Sargassum-based Alginate ion-exchange beads as a bio-based alternative in Trinidad and developing nations for dealing with heavy metal ion waste, offering superior heavy metal adsorption performance and supporting resource circularity., (© 2024. The Author(s).)

Macroporous ion exchange resin has excellent selectivity to nitrogen (N), phosphorus (P) and partially soluble refractory organic compounds contained in the secondary effluent of wastewater treatment plants (WWTP). In this study, macroporous ion exchange resins were chosen as an alternative to single biochemical nitrogen removal processes. Various conditions were examined to optimize adsorption performance, and the adsorption mechanism was explored through isotherm fitting, thermodynamic parameter calculation, and kinetic analysis. The experiment demonstrated that the resin exhibited strong selectivity for nitrate (NO 3 - ) and achieved an equilibrium adsorption amount of 9.8924 mg/g and an equilibrium adsorption time of 60 min at 25 °C. The resin denitrification pilot plant demonstrated stable operation for two months and achieved COD<20 mg/L, TN < 1.5 mg/L, and NH 4 + -N<0.5 mg/L. The removal rates of COD, TP, NH 4 + -N, NO 3 - -N, and TN were 41.65%, 42.96%, 55.37%, 91.8%, and 90.81%, respectively. After the resin was regenerated, the removal rates of NO 3 - -N, TN and the regeneration recovery rate were above 90%. Through cost analysis, the treatment cost of the pilot plant is only 0.104 $/m 3 . This study presents a practical, low-cost, and efficient treatment method for the deep treatment of secondary effluent from WWTP in practical engineering, providing new ideas and theoretical guidance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Ion exchange chromatography is a method that uses the different surface charges of trypanosomes and blood cells to separate them. This makes it possible to use molecular and immunological methods to diagnose or study these protozoans. DEAE-cellulose resin is commonly used to perform this method. The goal of this study was to compare three novel chromatographic resins designated as PURIFICA™ (Y-C2N®, Y-HONOH®, and Y-CNC3®). The resins were evaluated based on their ability to isolate the parasite, purification time, examination of parasite viability and morphology, and trypanosome recovery potential after passing through the columns. In terms of the evaluated parameters, there was no significant difference between DEAE-cellulose and the three tested resins in most experiments. However, PURIFICA™ (Y-C2N®, Y-HONOH®, and Y-CNC3®) resins are less expensive and easier to prepare than DEAE-Cellulose, making them an alternative for the purification of Trypanosoma evansi., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Taste masking is critical to improving the compliance of pediatric oral dosage forms. However, it is challenging for extremely bitter lisdexamfetamine dimesylate (LDX) with a long half-life and given in large dose. The present study aims to develop an immediate-release, taste-masked lisdexamfetamine chewable tablet. Lisdexamfetamine-resin complexes (LRCs) were prepared using the batch method. The molecular mechanism of taste masking was explored by PXRD, PLM, STA, and FT-IR. The results showed that taste masking was attributed to the ionic interaction between drug and the resin. The ion exchange process conformed to first-order kinetics. The rate-limiting step of drug release was the diffusion of ions inside the particles, and the concentration of H + was the key factor for immediate release. The masking efficiency of the prepared LRCs in saliva exceeded 96%, and the drug could be completely released within 15 min in aqueous HCl (pH 1.2). Furthermore, the SeDeM expert system was used for the first time to comprehensively study the powder properties of LRCs and to quickly visualize their defects (compressibility, lubricity/stability, and lubricity/dosage). The selection of excipients was targeted rather than traditional screening, thus obtaining a robust chewable tablet formulation suitable for direct compression. Finally, the difference between chewable tablets containing LRCs and chewable tablets containing lisdexamfetamine dimesylate was compared by in vitro dissolution test, electronic tongue, and disintegration test. In conclusion, an immediate-released, child-friendly lisdexamfetamine chewable tablets without bitterness was successfully developed by the QbD approach, using the SeDeM system, which may help in further development of chewable tablets., (© 2023. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

The purpose of this investigation was to formulate and evaluate the interaction between cation exchange resins and verapamil hydrochloride. The uptake studies were conducted using the rotating bottle apparatus. The Langmuir-like equation was applied to the experimental data and the maximum drug loading was determined from the Langmuir-like parameters. The drug-resin complexes were evaluated using XRD, SEM, and particle size analysis. Release studies were performed using USP dissolution apparatus 2. The resin with the lowest percentage of cross-linking had the highest uptake capacity. The percent increase in particle size due to complexation was found to be associated with drug loading; the highest drug loading had the highest increase in particle size. The X-ray diffraction patterns of the resins and the drug-resin complexes showed that they were both amorphous. The maximum drug release was approximately 40% when conventional dissolution testing was used. Results showed that sink conditions could not be maintained using conventional dissolution methods. Maximum drug release increased dramatically by increasing the volume of samples withdrawn and fresh dissolution medium added. Excellent correlation was obtained between sample volume and drug release rate with an R-value of 0.988. Particle diffusion-controlled model and film diffusion-controlled model were both applied to the experimental data. The results indicated that the rate-limiting step is the diffusion of the exchanging cations through the liquid film. The modified release formulation was prepared successfully and correlated very well with the USP monograph for verapamil hydrochloride extended release capsules., (© 2023. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Polyallylamine (PAA) has been utilized as a salt tolerant anion exchange chromatography ligand in downstream processing of biopharmaceuticals. We have developed novel MMC resins based on PAA polymer ligand partially modified with hydrophobic butyl or phenyl group. The resulting hydrophobic modified PAA ligand reduced HCP level to 12% (21-23 ppm) under 6 mS/cm in a flow-through polishing step of mAb, while not modified PAA ligand showed only 79% (145 ppm). We also found that structure of hydrophobic groups in the ligand mainly influenced on mAb yield. That is 25% increase of phenyl group modification ratio reduces mAb yield from 95% to 90%. On the other hand, modification with butyl group kept mAb yield more than 95%. The optimized ligand structure displayed a wide operational conductivity range. Extended purification studies of mAb using the MMC resin in the flow-through polishing step were carried out under optimized pH and conductivity condition as determined in a DOE study. The study revealed that the MMC resin was effective for developing one-step flow-through polishing workflow for mAb purification. In addition, the MMC flow-through polishing step could be directly coupled with a specified CEX chromatography step to efficiently remove mAb aggregates from 2.3% to <1.0% to achieve a biopharmaceutical-grade quality and a high yield of mAb (>93%) with a high loading capacity around 1000 mg/mL-resin. This new MMC resin will be useful in future mAb manufacturing platforms comprising of a robust and cost-effective flow-through polishing step., (Copyright © 2021. Published by Elsevier B.V.)

The impact of key classes of compounds found in wine on protein removal by the ion-exchange resin, Macro-Prep ® High S, was examined by adsorption isotherm experiments. A model wine system, which contained a prototypical protein Bovine Serum Albumin (BSA), was used. We systematically changed concentrations of individual chemical components to generate and compare adsorption isotherm plots and to quantify adsorption affinity or capacity parameters of Macro-Prep ® High S ion-exchange resin. The pH (hydronium ion concentration), ethanol concentration, and prototypical phenolics and polysaccharide compounds are known to impact interactions with proteins and thus could alter the adsorption affinity and capacity of Macro-Prep ® High S ion-exchange resin. At low equilibrium protein concentrations (< ~0.3 (g BSA)/L) and at high equilibrium protein concentrations in model wines at various pH, the adsorption behavior followed the Langmuir isotherm, most likely due to the resin acting as a monolayer adsorbent. The resulting range of BSA capacity was between 0.15-0.18 (g BSA)/(g Macro-Prep ® High S resin). With the addition of ethanol, catechin, caffeic acid, and polysaccharides, the protein adsorption behavior was observed to differ at higher equilibrium protein concentrations (> ~0.3 (g BSA)/L), likely as a result of Macro-Prep ® acting as an unrestricted multilayer adsorbent at these conditions. These data can be used to inform the design and scale-up of ion-exchange columns for removing proteins from wines.

In this study, we present results obtained on the enantioseparation of some cationic compounds of pharmaceutical relevance, namely tetrahydro-ß-carboline and 1,2,3,4-tetrahydroisoquinoline analogs. In high-performance liquid chromatography, chiral stationary phases (CSPs) based on strong cation exchanger were employed using mixtures of methanol and acetonitrile or tetrahydrofuran as mobile phase systems with organic salt additives. Through the variation of the applied chromatographic conditions, the focus has been placed on the study of retention and enantioselectivity characteristics as well as elution order. Retention behavior of the studied analytes could be described by the stoichiometric displacement model related to the counter-ion effect of ammonium salts as mobile phase additives. For the thermodynamic characterization parameters, such as changes in standard enthalpy Δ(ΔH°), entropy Δ(ΔS°), and free energy Δ(ΔG°), were calculated on the basis of van't Hoff plots derived from the ln α vs. 1/T curves. In all cases, enthalpy-driven enantioseparations were observed with a slight, but consistent dependence of the calculated thermodynamic parameters on the eluent composition. Elution sequences of the studied compounds were determined in all cases. They were found to be opposite on the enantiomeric stationary phases and they were not affected by either the temperature or the eluent composition., Competing Interests: Declaration of Competing Interest Authors declare no conflict of interest., (Copyright © 2021. Published by Elsevier B.V.)

A strongly basic ion-exchange resin catalyst was reported to exhibit a high catalytic activity in transesterification to produce a bio-based surfactant, sugar ester under mild condition. However, the side-reactions to decompose the reactant and the product were found to occur. This study was aimed to improve the selectivity of sugar ester synthesis by newly focusing on the basicity of the resin. A weakly basic resin (Diaion WA20) with a lower mass transfer resistance suppressed the decompositions while maintaining synthesis rate. Controlling molar ratio of the reactants in the intraparticle reaction field also increased the reaction selectivity, 72.1% and product yield, 57.5%. Both values were drastically increased compared to the reported values with the strongly basic resin (selectivity 50.9%, yield 14.3%). This is the first knowledge to show a high catalytic activity of weakly basic resin. These results suggest that a more efficient continuous production process would be possible., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A Poly (3,4-ethylenedioxothiophene) (PEDOT)/UiO-66 composite was electrodeposited on an etched stainless-steel wire as head-space solid-phase microextraction (HS-SPME) coating. A robust, well controlled thickness, and uniform coating of metal organic framework composites can be realized by the electrodeposited strategy. The incorporated UiO-66 not only enhanced the uniformity and stability of the composite coating, but also effectively decreased the stacking phenomenon of PEDOT and improved its extraction efficiency, which was over 100 times higher than that of the PEDOT coating without UiO-66. The composite coating was used to enrich seven types of volatile organic compounds (VOCs) in ion-exchange resins, including methyl cyclohexane, benzene, toluene, ortho-xylene, styrene, para-xylene and divinyl-benzene. The results of adsorption isotherm analysis showed that π stacking effect played dominant role between the composite coating and VOCs in the extraction process. The composite coating was characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared and thermogravimetric analysis, respectively. A determination method for seven kinds of VOCs was established by HS-SPME coupled with gas chromatography-flame ionization detection (GC-FID). Under the optimal experimental conditions, the detection linear range (LRs) was 0.09-100 ng mL -1 , and the detection limit (LODs) was 0.03-0.06 ng mL -1 (S/N = 3). The method was applied for the migration detection of VOCs in four types of ion-exchange resin, which showed satisfactory recovery (84.5-117.2%)., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In the present work, was investigated the separation and purification procedure of the biogenic 1,3-propanediol (1,3-PD), which is a well-known valuable compound in terms of bio-based plastic materials development. The biogenic 1,3-PD was obtained as a major metabolite through the glycerol fermentation by Klebsiella pneumoniae DSMZ 2026 and was subjected to separation and purification processes. A strong acidic ion exchange resin in H + form was used for 1,3-PD purification from the aqueous solution previously obtained by broth flocculation. The eluent volume was investigated considering the removal of the secondary metabolites such as organic acids (acetic, citric, lactic, and succinic acids) and 2,3-butanediol (2,3-BD), and unconsumed glycerol. It was observed that a volume of 84 mL of ethanol 75% loaded with a flow rate of 7 mL/min completely remove the secondary metabolites from 10 mL of concentrated fermented broth, and pure biogenic 1,3-PD was recovered in 128 mL of the eluent.

This study examines the mechanisms of adsorption of anthocyanins from model aqueous solutions at pH values of 3, 6, and 9 by ion-exchange resins making the main component of heterogeneous ion-exchange membranes. This is the first report demonstrating that the pH of the internal solution of a KU-2-8 aromatic cation-exchange resin is 2-3 units lower than the pH of the external bathing anthocyanin-containing solution, and the pH of the internal solution of some anion-exchange resins with an aromatic (AV-17-8, AV-17-2P) or aliphatic (EDE-10P) matrix is 2-4 units higher than the pH of the external solution. This pH shift is caused by the Donnan exclusion of hydroxyl ions (in the KU-2-8 resin) or protons (in the AV-17-8, AV-17-2P, and EDE-10P resins). The most significant pH shift is observed for the EDE-10P resin, which has the highest ion-exchange capacity causing the highest Donnan exclusion. Due to the pH shift, the electric charge of anthocyanin inside an ion-exchange resin differs from its charge in the external solution. At pH 6, the external solution contains uncharged anthocyanin molecules. However, in the AV-17-8 and AV-17-2P resins, the anthocyanins are present as singly charged anions, while in the EDE-10P resin, they are in the form of doubly charged anions. Due to the electrostatic interactions of these anions with the positively charged fixed groups of anion-exchange resins, the adsorption capacities of AV-17-8, AV-17-2P, and EDE-10P were higher than expected. It was established that the electrostatic interactions of anthocyanins with the charged fixed groups increase the adsorption capacity of the aromatic resin by a factor of 1.8-2.5 compared to the adsorption caused by the π-π (stacking) interactions. These results provide new insights into the fouling mechanism of ion-exchange materials by polyphenols; they can help develop strategies for membrane cleaning and for extracting anthocyanins from juices and wine using ion-exchange resins and membranes.

In this letter, the innate ability of nitric oxide (NO) to inhibit platelet activation/adhesion/thrombus formation is employed to improve the hemocompatibility and in vivo accuracy of an intravascular (IV) potentiometric P CO 2 (partial pressure of carbon dioxide) sensor. The catheter-type sensor is fabricated by impregnating a segment of dual lumen silicone tubing with a proton ionophore, plasticizer, and lipophilic cation-exchanger. Subsequent filling of bicarbonate and strong buffer solutions and placement of Ag/AgCl reference electrode wires within each lumen, respectively, enables measurement of the membrane potential difference across the inner wall of the tube, with this potential changing as a function of the logarithm of sample P CO 2 . The dual lumen device is further encapsulated within a S -nitroso- N -acetyl-DL-penicillamine (SNAP)-doped silicone tube that releases physiological levels of NO. The NO releasing sensor exhibits near-Nernstian sensitivity toward P CO 2 (slope = 59.31 ± 0.78 mV/decade) and low drift rates (<2 mV/24 h after initial equilibration). In vivo evaluation of the NO releasing sensors, performed in the arteries and veins of anesthetized pigs for 20 h, shows enhanced accuracy (vs non-NO releasing sensors) when benchmarked to measurements of discrete blood samples made with a commercial blood gas analyzer. The accurate, continuous monitoring of blood P CO 2 levels achieved with this new IV NO releasing P CO 2 sensor configuration could help better manage hospitalized patients in critical care units.

A starch-based ion exchange resin (SIR) was synthesized by copolymerizing raw starch with sodium methallyl sulfonate and styrene. The structural and surface properties of the SIR were characterized by 13 C nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, gel permeation chromatography, scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis, Brunauer-Emmett-Teller surface area analysis, and laser particle size analysis. The SIR was physicochemically and thermally stable and resistant to acids, bases, and enzymes. In static adsorption tests, the SIR had decolorization ratios (DRs) for mixed dyestuffs in wastewater of up to 84.04%, which was higher than the DR for a synthetic ion exchange resin (001 × 7, DR 77.14%). In dynamic adsorption tests, the SIR bed had a DR of 99.85% and a wastewater handling capacity 25 times the column volume. After three adsorption-regeneration cycles, the DR of the resin bed had decreased by <7.5%. The properties of the SIR, particularly the adaptability of the SIR to continuous column adsorption, make the SIR suitable for removing dyestuffs from industrial wastewater and a potential substitute for traditional sorbents such as activated carbon and synthetic resins., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Efficient separation technologies are crucial to the environment and world economy. The challenge posed to scientists is how to engineer selectivity towards a targeted substrate, especially from multicomponent solutions. Polymer-supported reagents have gained a lot of attention in this context, as they eliminate a lot of inconveniences concerning widely used solvent extraction techniques. Nevertheless, the choice of an appropriate ligand for immobilization may be derived from the behavior of soluble compounds under solvent extraction conditions. Organophosphorus compounds play a significant role in separation science and technology. The features they possess, such as variable oxidation states, multivalence, asymmetry and metal-binding properties, highlight their status as a unique and versatile class of compounds, capable of selective separations proceeding through different mechanisms. This review provides a detailed survey of polymers containing phosphoric, phosphonic and phosphinic acid functionalities in the side chain and covers main advances in the preparation and application of these materials in separation science, including the most relevant synthesis routes (Arbuzov, Perkow, Mannich, Kabachnik-Fields reactions, etc.), as well as the main stages in the development of organophosphorus resins and the most important achievements in the field.

In this study, an ion exchange resin-based downstream-processing concept for imine reductase (IRED)-catalyzed reactions was investigated. As a model reaction, 2-methylpyrroline was converted to its corresponding product (S)-2-methylpyrrolidine with >99% of conversion by the (S)-selective IRED from Paenibacillus elgii B69. Under optimized reaction conditions full conversion was achieved using a substrate concentration of 150 and 500 mmol/L of d-glucose. Seven commercially available cation- and anion-exchange resins were studied with respect to their ability to recover the product from the reaction solution. Without any pretreatment, cation-exchange resins Amberlite IR-120(H), IRN-150, Dowex Monosphere 650C, and Dowex Marathon MSC showed high recovery capacities (up to >90%). A 150-ml preparative scale reaction was performed yielding ~1 g hydrochloride salt product with >99% purity. Any further purification steps, for example, by column chromatography or recrystallization, were not required., (© 2020 The Authors. Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers.)

Radioactive Cs ions are extremely harmful to the human body, causing cancers and other diseases. Treatments were performed on radioactive Cs present in wastewater after use in industrial or medical fields. Prussian blue (PB) has been widely used for the removal of Cs ions from water but its colloidal structure hinders reuse, making it problematic for practical use. To solve this problem, we used a commercial macroporous polymer resin as a PB matrix. To provide an efficient anchor for PB, the surface of the polymer resin was decorated with sodium dodecylbenzenesulfonate to produce a negatively charged surface. The successful chemical binding between the polymer resin and PB prevented leakage of the latter during adsorption and crosslinked structure of the matrix provided regeneration of the adsorbent. The adsorbent maintained its removal efficiency after five repeats of the regeneration process. The PB-based, Cs ion-exchange resin showed excellent selectivity toward Cs ions and good reusability, maintaining its high adsorption capacity., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Marinobacter hydrocarbonoclasticus is an oil-eating bacterium that possesses a large adhesion protein (MhLap) with the potential to bind extracellular ligands. One of these ligand-binding modules is the ~20-kDa PA14 domain (MhPA14) that has affinity for glucose-based carbohydrates. Previous studies showed this sugar-binding domain is retained on dextran-based size-exclusion resins during chromatography, requiring the introduction of glucose or EDTA to remove the protein from the column. Given the ready availability of such size-exclusion resins in biochemistry laboratories, this study explores the use of MhPA14 as an affinity tag for recombinant protein purification. Two different fusion proteins were tested: 1) Green fluorescent protein (GFP) linked to the N-terminus of the MhPA14 tag; and 2) the ice-binding domain from the Marinomonas primoryensis ice-binding protein (MpIBD) linked to the MhPA14 C-terminus by a TEV cut site. The GFP&#95;MhPA14 fusion visibly bound to Superdex, Sephadex, and Sephacryl resins, but did not bind to Sepharose. Using Superdex resin, dextran-affinity purification proved to be an effective one-step purification strategy for both proteins, superior to even nickel-affinity chromatography. Dextran-affinity chromatography was also the most effective method of separating the MhPA14 tag from MpIBD following TEV proteolysis, as compared to both nickel-affinity and ice-affinity methods. These results indicate that MhPA14 has potential for widespread use in recombinant protein purification., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Protein mobility at solid-liquid interfaces can affect the performance of applications such as bioseparations and biosensors by facilitating reorganization of adsorbed protein, accelerating molecular recognition, and informing the fundamentals of adsorption. In the case of ion-exchange chromatographic beads with small, tortuous pores, where the existence of surface diffusion is often not recognized, slow mass transfer can result in lower resin capacity utilization. We demonstrate that accounting for and exploiting protein surface diffusion can alleviate the mass-transfer limitations on multiple significant length scales. Although the surface diffusivity has previously been shown to correlate with ionic strength (IS) and binding affinity, we show that the dependence is solely on the binding affinity, irrespective of pH, IS, and resin ligand density. Different surface diffusivities give rise to different protein distributions within the resin, as characterized using confocal microscopy and small-angle neutron scattering (length scales of micrometer and nanometer, respectively). The binding dependence of surface diffusion inspired a protein-loading approach in which the binding affinity, and hence the surface diffusivity, is modulated by varying IS. Such gradient loading increased the protein uptake efficiency by up to 43%, corroborating the importance of protein surface diffusion in protein transport in ion-exchange chromatography., Competing Interests: The authors declare no competing interest.

Differences in the characteristics of seventeen commercial C-30 liquid chromatographic columns were studied for the separation of carotenoid isomers. A mixture consisting of nine xanthophyll and hydrocarbon carotenoids were separated under conditions carefully chosen to reveal changes in selectivity. The influence of the mobile phase composition, column temperature, and mobile phase flow rate were evaluated. Shape selectivity was characterized with Standard Reference Material (SRM) 869b Column Selectivity Test Mixture, for correlation with carotenoid retention behavior. Regular changes were observed across a broad spectrum of shape selectivity characteristics as indicated by SRM 869b. Better separations of carotenoid isomers were achieved with C-30 columns than were possible with C-18 columns, even after optimization of separation conditions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier B.V.)

Cupric ions are hazardous to human beings and their removal from the body is very necessary. The blends of IRP69H (AMBERLITE IRP-69 [H + ] RESIN), DC20H (DOWEX ™ 20 [H+] Resin), DMSCH (DOWEX™ MARATHON™ MSC [H+] Resin) and Kappa Carrageenan (κ-) were utilized for the removal of ions of Cu 2+ from the blood. They were subjected to docking studies which showed that there is no significant interaction with the blood albumin. IER dose of 0.5 mg/10mL of IRP69H/κ-, DMSCH/κ-, and DC20H/κ- was essential for the 2+ ion removal. At pH 5.4, optimal 2+ ions adsorption efficiency was attained. The adsorption capacities of 2+ were in the order of IRP69H/κ->DC20H/κ->DMSCH/κ-. While the data fitted well to Freundlich, Langmuir and Dubinin-Radushkevich. Pseudo-second order was followed for 2+ adsorption for DMSCH/κ- and DC20H/κ- while the pseudo-first order was demonstrated well for IRP69H/κ-.

It is essential to mitigate the risk of exposure to effluent organic matter (EfOM) in aquatic environments to ensure safe wastewater recycling. Magnetic ion-exchange (MIEX) resin adsorption combined with ozonation could provide EfOM removal. However, the poor understanding of the influences of the parameters and mechanisms in the hybrid process has restricted the applications. In this study, the response surface methodology was used to reveal the interactions of the major operation parameters. The degradation behaviour of the EfOM was investigated by using spectroscopy combined with mathematical methods. The effect of the pH on the EfOM removal was also analysed. The maximum efficiency of the removal of dissolved organic carbon (DOC) was 59.77% at the optimal MIEX resin dosage of 7.97 mL/L, ozone concentration of 8 mg/L, agitation speed of 199.84 r/min, and pH of 9.98. The ozonation was superior to resin adsorption in the removal of 1054-Da compounds, while the resin adsorption was advantageous in the removal of 4168-Da compounds. Three fluorescent components (C1, C2, and C3) were more easily subjected to external perturbation than the DOC and ultraviolet absorbance at 254 nm in the oxidation processes. The MIEX resin exhibited low efficiencies of removal of the fluorescent substances. A synchronous fluorescence analysis coupled with a two-dimensional correlation analysis revealed that the variation in EfOM followed the order of fulvic-to humic-like substances in the hybrid process of MIEX and the following ozonation. The pH was the most significant influencing factor in the hybrid process., (Copyright © 2019. Published by Elsevier Ltd.)

Biochemical, biophysical, and structural studies of membrane proteins rely on the availability of highly pure and monodisperse membrane protein samples. One of the most powerful methods for isolation of the membrane protein of interest is affinity purification. This methodology typically relies on engineering an affinity tag into the protein of interest and an affinity resin that specifically recognizes the tag, allowing one to purify the target protein in a single step. In some cases, the affinity purification procedure is combined with additional steps to increase the purity and homogeneity of the final protein sample. Here, we describe several protocols for affinity purification of TSPO, a small membrane protein. The techniques we use include immobilized metal affinity chromatography (IMAC) and strep-II tag-based streptavidin affinity chromatography.

Clarithromycin (CLA) is an extremely bitter macrolide antibiotic used to treat paediatric and adult infections. The bitter taste affects patient adherence and may compromise therapy. This research developed a taste masked CLA resinate using Indion® 234, a weak acidic cation exchange resin. The factors affecting formation of the CLA-resin complex were assessed. Design of experiments was used to optimize response while evaluating input variables such as temperature, CLA-resin ratio,stirring time and pH. CLA loading efficiency was determined spectrophotometrically and CLA release using USP Apparatus II. Differential Scanning Calorimetry (DSC), Scanning Electron Microscop (SEM), Fourier Transform Infrared (FT-IR) Spectroscopy and X-ray Diffraction (XRD) were used to confirm complex formation. A spectrophotometric method was used to assess taste evaluation. The optimum CLA-resin ratio, temperature, and stirring time were 1:4, 80 °C, 3 hours, respectively, at pH 8. Characterization techniques revealed that CLA was crystalline and the complex amorphous in nature. FT-IR spectra of resinate revealed the absence of resonance due to the tertiary amine functional group that is responsible for the bitter taste of CLA. CLA was stable in simulated salivary fluid and was released within 3 hours in gastric fluid. All CLAresin batches revealed complete taste masking. Taste analysis highlighted the improvement of taste masking properties of the resinate as the CLA to resin ratio, increased.

Zwitterionic chiral ion-exchange selectors (ZWIX) obtained by conjugation of quinine and 2-aminocyclohexanesulfonic acid via a carbamate bond were immobilized on three different silica particle types, viz. 120 Å 3 μm fully porous particles (FPP), 200 Å 3 μm FPP and 160 Å 2.7 μm superficially porous particles (SPP). Selector densities were determined by elemental analysis and the porosities of packed columns measured by inverse size exclusion chromatography with polystyrene standards. Liquid chromatographic tests with a set of chiral zwitterionic, acidic and basic analytes showed that the surface chemistry was successfully transferred to the distinct particle morphologies. The chromatographic performance of the three columns was evaluated by acquiring van Deemter curves. The results showed that the column packed with the SPP particles gives the best performance and kinetic plots further demonstrated that they represent the most favorable compromise in terms of speed, efficiency and pressure drop. Sub-minute separations could be accomplished at much lower pressure drop on the core-shell column, e.g. 2-amino-2-phenylbutyric acid was baseline separated in less than 15 s on a 5 cm long column. The Maxwell effective medium theory with second order approximation was applied to calculate effective diffusion in the mesoporous zones of SPP and FPP, which allowed eventually to deconvolute the individual peak dispersion contributions (h a , h b , h c,m , h c,s , h c,ads ). The efficiency gain of the 160 Å SPP column compared to the 120 Å FPP (benchmark) column was mainly due to lower eddies (h a ), smaller c-term accounting for slow adsorption-desorption kinetics in enantioselective chromatography (h c,ads ), and also due to lower stationary mass transfer resistance (h c,s ). Enhanced effective diffusion (D eff ) in the SPP column contributed to a lower longitudinal diffusion (h b ). In contrast, the mobile phase mass transfer coefficient was similar in the two columns leading to comparable h c,m contributions. This study discloses some options for improvement of the efficiency of ZWIX-type chiral columns such as replacing narrow pore (120 Å) by wide pore (200 Å) particles, substituting FPP by SPP and reducing the selector density on the surface., (Copyright © 2019 Elsevier B.V. All rights reserved.)

We develop a technique for the sorption of inulinase from Kluyveromyces marxianus on the KU-2 matrix cation-exchanger. The most appropriate conditions for immobilization are: 25 °C, pH 4.5, incubation time 1.5 h, protein content during immobilization 10 mg/g of carrier. At higher (20-100 mg/g) concentrations, inulinase forms local high-concentration domains on the ion-exchanger surface, the enzyme is adsorbed on the protein, not on the carrier. 62% of the initial catalytic activity of inulinase is immobilized on KU-2 by the adsorption method. Upon the enzyme immobilization on KU-2, the number of unordered structures in the protein is reduced by ~10%, that points to the compaction of the molecule. Hydrogen bonds are formed only between the sulfo groups of carrier and the protein molecule, without affecting other structures of the cation exchanger. The highest activity of the inulinase immobilized on KU-2 was observed at 70 °C (cf. 50 °C for the native enzyme). Heating of the solution for 60 min in the temperature range of 50-80 °C failed to inactivate completely the immobilized enzyme; the complete loss of its ability to hydrolyze inulin was achieved only after more than 1 h incubation at 90 °C., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The presence of 2-acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole (THI) in beverages has raised several concerns regarding its toxicity to humans. The sample preparation and detection of THI in complex matrices is challenging owing to its high water solubility. Here we reported a rapid sample preparation method based on dispersive micro-solid phase extraction (D-μ-SPE) using polymer cation exchange sorbent as sorbent for the extraction of THI from beverage samples. THI was detected by high performance anion exchange chromatography-pulsed amperometric detector (HPAEC-PAD) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The experimental parameters of D-μ-SPE on extraction efficiency were carefully optimized. Under the optimized conditions, high recoveries (83.4-96.1%) and good reproducibility (%RSD ≤ 8.7%) were obtained using D-μ-SPE-HPAEC-PAD and D-μ-SPE-HPLC-MS/MS. Limit of quantification was 75 ng/mL for HPAEC-PAD and 5 ng/mL for HPLC-MS/MS. This work proves the potential application the newly developed method for the quantification of THI in beverages containing caramel color., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Over the past century, atmospheric nitrogen deposition (N dep ) has increased across the western United States due to agricultural and urban development, resulting in degraded ecosystem quality. Regional patterns of N dep are often estimated by coupling direct measurements from large-scale monitoring networks and atmospheric chemistry models, but such efforts can be problematic in the western US because of complex terrain and sparse sampling. This study aimed not only to understand N dep patterns in mountainous ecosystems but also to investigate whether isotope values of lichens and throughfall deposition can be used to determine N dep sources, and serve as an additional tool in ecosystem health assessments. We measured N dep amounts and δ 15 N in montane conifer forests of the Greater Yellowstone Ecosystem using canopy throughfall and bulk monitors and lichens. In addition, we examined patterns of C:N ratios in lichens as a possible indicator of lichen physiological condition. The isotopic signature of δ 15 N of N dep helps to discern emission sources, because δ 15 N of NO x from combustion tends to be high (-5 to +25‰) while NH x from agricultural sources tends to be comparatively low (-40 to -10‰). Summertime N dep increased with elevation and ranged from 0.26 to 1.66 kg ha -1 . N dep was higher than expected in remote areas. The δ 15 N values of lichens were typically -15.3 to -10‰ suggesting agriculture as a primary emission source of deposition. Lichen %N, δ 15 N and C:N ratios can provide important information about N dep sources and patterns over small spatial scales in complex terrain., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Aiming at realizing heavy metal recycling and resource utilization, a carbon-based iron catalyst (Fe@C) was synthesized through a resin carbonization method, and adopted for peroxymonosulfate (PMS) activation to remove bisphenol S (BPS), an emerging aquatic contaminant. This study demonstrated that Fe@C exhibited excellent catalytic potential for BPS degradation with a relatively low activation energy (E a  = 29.90 kJ/mol). Kinetic factors affecting the activation performance were thoroughly investigated. The obtained results indicated that Fe@C composite exhibited the superior uniformity with carbon as the framework and granular iron oxide as the coverage. pH increase could cause the inhibitive effect on BPS degradation, while the increasing catalyst loading (0.05-0.5 g/L) was conducive for the catalytic performance of Fe@C, with an optimal PMS concentration at 1.0 mM. A negative influence on BPS degradation was obtained in the presence of SO 4 2- , HCO 3 - and lower concentration of Cl - (0-20 mM), compared to the promotion at higher concentration of Cl - (>50 mM). Based on the electron spin resonance (ESR) monitoring and radical scavenging results, it is demonstrated that singlet oxygen, a non-radical species, emerged together with ·SO 4 - and ·OH for BPS degradation. A three-channel catalytic mechanism was verified through typical characterizations. Furthermore, the degradation pathway of BPS was proposed based on the identified intermediates. This novel carbon-based activator for PMS showed notable potential for the waste resin recycling and water decontamination. A novel Fe-based activator carbonized from a saturated resin exhibits excellent performance for Bisphenol S degradation with activated peroxymonosulfate., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A novel functional ion-exchange/adsorption metal organic resin (MOR), TEBAC-HKUST-1, was prepared and characterized. Ethanedithiol was used as the grafting agent to introduce thiol groups onto HKUST-1, and 4-vinylbenzyl chloride was then grafted onto SH-HKUST-1 using thiol groups. Finally, the quaternary ammonium functional group was immobilized onto the carrier by performing a quaternization reaction. The structure and property of TEBAC-HKUST-1 MOR were characterized by TGA, N 2 adsorption-desorption, FTIR, SEM, and XRD. TEBAC-HKUST-1 MOR was used to remove metal cyanide complexes from wastewater. The adsorption was rapid, and the metal cyanide complexes including Pt(CN) 4 2- , Co(CN) 6 3- , Cu(CN) 3 2- , and Fe(CN) 6 3- were removed in 30 min. TEBAC-HKUST-1 MOR exhibited a high stability in neutral and weak basic aqueous solutions. Furthermore, Pt(II) could be efficiently recovered through two-step elution. The recovery rate of Pt(II) for five cycles were over 92.0% in the mixture solution containing Pt(CN) 4 2- , Co(CN) 6 3- , Cu(CN) 3 2- , and Fe(CN) 6 3- . The kinetic data were best fitted with the pseudo second-order model. Moreover, the isothermal data were best fitted with the Langmuir model. The thermodynamic results show that the adsorption is a spontaneous and exothermic process. TEBAC-HKUST-1 MOR not only exhibited excellent ability for the rapid removal of metal cyanide complexes, but also provided a new idea for the extraction of noble metals from cyanide-contaminated water.

Electrodialysis and electrodeionization are separation processes whose performance depends on the quality and properties of ion-exchange membranes. One of the features that largely affects these properties is heterogeneity of the membranes both on the macroscopic and microscopic level. Macroscopic heterogeneity is an intrinsic property of heterogeneous ion-exchange membranes. In these membranes, the functional ion-exchange component is dispersed in a non-conductive binder. The functional component is finely ground ion-exchange resin particles. The understanding of the effect of structure on the heterogeneous membrane properties and behavior is thus of utmost importance since it does not only affect the actual performance but also the cost and therefore competitiveness of the aforementioned separation processes. Here we study the electrokinetic behavior of cation-exchange resin particle systems with well-defined geometrical structure. This approach can be understood as a bottom up approach regarding the membrane preparation. We prepare a structured cation-exchange membrane by using its fundamental component, which is the ion exchange resin. We then perform an experimental study with four different experimental systems in which the number of used cation-exchange particles changes from 1 to 4. These systems are studied by means of basic electrochemical characterization measurements, such as measurement of current-voltage curves and direct optical observation of phenomena that occur at the interface between the ion-exchange system and the adjacent electrolyte. Our work aims at better understanding of the relation between the structure and the membrane properties and of how structure affects electrokinetic behavior of these systems.

Nutrient recovery from municipal wastewater was evaluated using anion exchange media loaded with hydrated ferric oxide (HFO) and copper (Cu 2+ ) (Dow-HFO-Cu resin) to selectively capture phosphate, followed by clinoptilolite for ammonium removal and recovery. Nutrients were concentrated in the regenerants and recovered as precipitated struvite. Media exchange capacity after multiple ion exchange cycles was determined using permeate from an anaerobic membrane bioreactor (AnMBR) treating synthetic or actual municipal wastewater from a full-scale water reclamation facility. Regeneration through five ion exchange cycles using relatively low concentration regenerant solution (2% NaCl and 0.5% NaOH) resulted in the highest phosphate exchange capacity and phosphate recovery. This regenerant also provided the most consistent ammonium recovery. Column tests treating AnMBR permeate were performed over five ion exchange cycles; Dow-HFO-Cu resin exchange capacities ranged from 1.6 to 2.8 mg PO 4 -P/g dry media. A maximum of 94% of the removed phosphate was recovered during regeneration. The rate and extent of regeneration was insensitive to regenerant salt concentrations in the range investigated. Precipitation using a mixture of the spent regeneration brines from the Dow-HFO-Cu resin and clinoptilolite columns produced low molar ratios of Mg:NH 4 :PO 4 , suggesting that the recovered product was not pure struvite. PRACTITIONER POINTS: Ion exchange-precipitation for the removal and recovery of PO 4 3 - and NH 4 + from AnMBR permeate is a promising technology. 2% NaCl + 0.5% NaOH regeneration solution provided the most consistent exchange performance for both phosphate and ammonium recovery. Regenerated Dow-HFO-Cu resin exchange capacity was consistently less than the virgin resin, likely due to copper leaching during regeneration. Molar ratios in the precipitates suggested that the precipitated material was not pure struvite., (© 2019 Water Environment Federation.)

Conventional sorption media are inefficient for phosphorus removal from wastewater due to preference for competing species such as sulphate, nitrate and organics. This work investigates whether the use of hybrid ion exchange resins effectively negates such concerns. Trials were conducted with a hybrid anion exchange (HAIX) media which was preloaded with different background constituents and operated over multiple regeneration cycles to ascertain the likely impacts. The work revealed that whilst the impact of the other constituents was seen in regards to direct competition, the major impact was on reduction of the rate of intraparticle mass transfer through sorption of the constituents onto the base resin thereby reducing the Donnan membrane effect. Comparison of the impact of the background water constituents on the individual components (hybrid resin, base resin, nanoparticles) revealed the importance of the nanoparticle whereby they effectively transform the ion exchange media into a mono component absorber for phosphorus that enables sustained removal even in complex wastewaters., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The electro-kinetic instability in a pressure driven shear flow near an ion exchange membrane is considered. The electrochemical system, through which an electrical potential drop is applied, consists in a polarization layer in contact with the membrane and a bulk. The numerical investigation contained two aspects: analysis of the instability modes and description of the Lagrangian transport of fluid and ions. Regarding the first aspect, the modes were analyzed as a function of the potential drop. The analysis revealed how the spatial distribution of forces controls the dynamics of vortex association and dissociation. In particular, the birth of a counter-clockwise vortex between two clockwise vortices, and the initiation of clusters constituting one or two envelopes wrapping a vortex group, were examined. In regards to the second aspect, the trajectories were computed with the fourth order Runge Kutta scheme for the time integration and with the biquadratric upstream scheme for the spatial and time interpolation of the fluid velocity and the ion flux. The results for the periodic mode showed two kinds of trajectories: the trochoidal motion and the longitudinal one coupled with a periodic transverse motion. For the aperiodic modes, other mechanisms appeared, such as ejection from the mixing layer, trapping by a growing vortex or merging vortices. The analysis of the local velocity field, the vortices' shape, the spatial distribution of the forces and the ion flux components explained these trajectories.

We employed a new dry coating process with mild-intensity vibration to prepare a 100-µm-sized microparticle capable of prolonged release of a drug. To accomplish this without using a binder, a series of laboratory-made acrylic latexes with different glass transition temperatures (Tg) ranging from 30 °C to 80 °C were employed as coating agents, and the effects of Tg and powdering method of the coating agents on coating performance were investigated. The laboratory-made acrylic latexes were powdered by spray-drying (SD) or freeze-drying (FD). Diclofenac sodium (DS)-loaded ion-exchange-resin with particle size ∼100 µm was used as a core particle. The process utilized vibrations with amplitude of 0.5 mm and frequency of 90 Hz to form an ordered mixture composed of the core particles with the loosely-layered coating agents. Subsequently, the coating agents were fixed mechanically on the core particle by impaction of zirconia beads. The coating agents powdered by FD showed higher coating efficiencies than those powdered by SD, irrespective of the differences in Tg values. Among the coating agents powdered by FD, the particles coated at Tg = 60 °C exhibited the most prolonged drug-release, although the coating efficiency was not the highest. In our proposed process utilizing mild vibration, we demonstrated that adjusting the Tg of the coating agents is crucial to the formation of binder-free multiple coating layers for prolonged drug release., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This method allows the separation of trypanosomes, parasites responsible for animal and human African trypanosomiasis (HAT), from infected blood. This is the best method for diagnosis of first stage HAT and furthermore this parasite purification method permits serological and research investigations. HAT is caused by Tsetse fly transmitted Trypanosoma brucei gambiense and T. b. rhodesiense. Related trypanosomes are the causative agents of animal trypanosomiasis. Trypanosome detection is essential for HAT diagnosis, treatment and follow-up. The technique described here is the most sensitive parasite detection technique, adapted to field conditions for the diagnosis of T. b. gambiense HAT and can be completed within one hour. Blood is layered onto an anion-exchanger column (DEAE cellulose) previously adjusted to pH 8, and elution buffer is added. Highly negatively charged blood cells are adsorbed onto the column whereas the less negatively charged trypanosomes pass through. Collected trypanosomes are pelleted by centrifugation and observed by microscopy. Moreover, parasites are prepared without cellular damage whilst maintaining their infectivity. Purified trypanosomes are required for immunological testing; they are used in the trypanolysis assay, the gold standard in HAT serology. Stained parasites are utilized in the card agglutination test (CATT) for field serology. Antigens from purified trypanosomes, such as variant surface glycoprotein, exoantigens, are also used in various immunoassays. The procedure described here is designed for African trypanosomes; consequently, chromatography conditions have to be adapted to each trypanosome strain, and more generally, to the blood of each species of host mammal. These fascinating pathogens are easily purified and available to use in biochemical, molecular and cell biology studies including co-culture with host cells to investigate host-parasite relationships at the level of membrane receptors, signaling, and gene expression; drug testing in vitro; investigation of gene deletion, mutation, or overexpression on metabolic processes, cytoskeletal biogenesis and parasite survival.

In this work, hypercrosslinked strong anion-exchange polymer resins (HXLPP-SAX) were synthesized and evaluated as solid-phase extraction (SPE) sorbents for extracting fluoroquinolones (FQs) in milk samples. These particles were prepared using a protocol that was facile and cost-effective by combining hypercrosslinking reactions and quaternisation reactions in one step. After the synthesis, the morphological properties and anion-exchange, adsorption, and selectivity performances of the HXLPP-SAX resins were characterized and evaluated. It was shown that the polymers were monodisperse microspheres, with the mean diameters of 2-4 μm, ion-exchange capacity (IEC) of 0.311 meq/g, and specific surface area more than 1000 m 2 /g. The resins applied as SPE sorbents possessed high selectivity in the extraction of amphoteric compounds (enoxacin and enrofloxacin as the representatives) followed by HPLC-UV analysis, as compared to commercially available strong anion-exchange sorbents (Oasis MAX). The SPE-HPLC-UV method was fully validated and exhibited good linearity (10-2000 ng/g, R 2 ≥ 0.997), low limits of detection (2.8-5.1 ng/g), good recoveries (85.8%-117.9%, RSDs ≤ 7.1%) and precisions (intra-day RSDs ≤ 7.7% and inter-day RSDs ≤ 9.4%). Then the method was performed the selective enrichment of six FQs (enoxacin, norfloxacin, ciprofloxacin, lomefloxacin, enrofloxacin, and sparfloxacin) in milk samples. The present results demonstrated that the proposed resins exhibited a promising potential for the enrichment and determination of FQ residues in milk samples as well as in other samples with complex matrices., (Copyright © 2018. Published by Elsevier B.V.)

Methionine is an essential sulfur-containing amino acid for organisms. The separation and purification are important for the production of l-methionine from fermentation broth. In this work, the adsorption properties for l-methionine separation of ten macroporous resins were firstly evaluated. Macroporous cation resin D72 showed the best adsorption capacity (52.37 mg/g) and desorption rate (99.12%). The adsorption kinetics of l-methionine on D72 resin followed the pseudo second-order model and adsorption isotherm fitted well to the Sips model, the adsorption process mainly followed a physisorption mechanism. D72 resin packed columns were then used in the batch separation of fermentation broth, the operation parameters were optimized during the dynamic adsorption and desorption experiments. Under the optimized conditions: fermentation broth adjusted to pH = 2, loading flow rate at 2 BV/h, loading volume 55 mL, 1 mol/L NH 3 ·H 2 O as eluent, elution flow rate at 2 BV/h, column height-diameter ratio at 14:1, excellent recovery and purity of l-methionine (82.37% and 85.69%, respectively) could be achieved., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The objective of the study is to obtain the modified zeolite powders and to apply these materials as active fillers in the dental composites with the remineralizing potential. Three different synthesis pathways were applied to receive LTA-type (Linde A-type) zeolites. All zeolites were subjected to the ion exchange process and mineralization of surface with hydroxyapatite (HA) layer. As a result a calcium form and surface modified form of these materials were prepared. The effectiveness of each modification process was confirmed by X-ray Diffractometry, Infrared and Raman Spectroscopy. Materials were also characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy and nitrogen adsorption/desorption measurements. The remineralizing potential was specified as an ability to release calcium ions during the incubation in saline with the use of Inductively Coupled Plasma-Mass Spectrometry. The obtained zeolite fillers were placed in the organic matrix to create photopolymerizable composites with potential dental applications. The homogeneity of the filler distribution in polymeric matrix was checked by the Raman spectra mapping. Composites containing calcium form of zeolites as well as zeolites with the HA layer proved to have the ability to release calcium ions during incubation in saline in the amount comparable to calcium phosphates-filled composites or even higher than dental glass-filled composites. The ability to release calcium ions, together with good mechanical properties and mass stability testify the suitability of prepared composites in potential dental applications., (Copyright © 2018 Elsevier B.V. All rights reserved.)

This study investigated the applicability of fluorescence excitation-emission matrix spectroscopy (EEMS) to assess total trihalomethane formation potentials (TTHMFPs) and the ability of magnetic ion exchange (MIEX ® ) resin to reduce TTHMFP. We treated a surface water and secondary wastewater effluent with MIEX mimicking full-scale operation by repeatedly exposing the same resin batch to additional feed water, with batches ranging from 500 to 5,000 resin bed volumes. Results showed that MIEX was more effective at removing or reducing ultraviolet absorbance (UVA 254 ), dissolved organic carbon (DOC), and TTHMFP in surface water than in secondary effluent. The greater UVA 254 , DOC and TTHMFP removal for surface waters was explained by the stronger affinity of MIEX for terrestrial dissolved organic matter (DOM) compared to microbial DOM. Fluorescence EEMS results showed that the ratio between terrestrial and microbial fluorescent signals of DOM was significantly greater in surface water than in secondary effluent. Fluorescence surrogate parameters were strongly correlated with TTHMFP, namely, fluorescence intensity of humic-like peak C (R 2 = 0.98, p < 0.01), protein-like peak T (R 2 = 0.96, p < 0.01), and fulvic-like peak A (R 2 = 0.87, p < 0.01). Correlations between fluorescence surrogate parameters and TTHMFP were substantially stronger than correlations between DOC and TTHMFP. Overall, the results indicate that fluorescent parameters extracted from EEMS data can be used as quick surrogate parameters to monitor TTHMFP for a diverse group of raw and MIEX-treated waters.

We assessed the relationship between the diffusive gradient in thin film (DGT) technique using the new ion-exchange resin Ambersep GT74 and the uptake of mercury (Hg) by a model plant cultivated on metal-contaminated agricultural soils under greenhouse conditions. Based on the total Hg content, 0.37 to 1.17% of the Hg passed to the soil porewater from the solid phase, and 2.18 to 9.18% of the Hg is DGT-available. These results were confirmed by calculating the R value (the ratio of the concentrations of bioavailable Hg measured by DGT and soil solution), which illustrated the strong bonding of Hg to the solid phase of soil and its extremely low mobility. Only inorganic Hg 2+ species were found in the metal-contaminated agricultural soils, as determined by a high-performance liquid chromatography-cold vapor atomic fluorescence spectrometry speciation analysis. The Hg was distributed in Miscanthus × giganteus organs in the following order for all sampling sites: roots (55-82%) >> leaves (8-27%) > stems (7-16%) > rhizomes (4-7%). Environ Toxicol Chem 2019;38:321-328. © 2018 SETAC., (© 2018 SETAC.)

Effect of turbidity on the removal of organic micropollutant (carbamazepine, CBZ) through magnetic ion exchange (MIEX) resin combined with ultrafiltration (UF) was investigated in this study. The purification behaviors of the MIEX/UF processes were studied through scanning electron microscopy, high-performance liquid chromatography, zeta potential and particle size distribution analyses. The experimental results show that 64-74% of CBZ in different turbidities could be removed by MIEX resin under the optimum dose and contact time, while water sample with turbidity of 20 ± 1.1 NTU present minimum CBZ removal rate of 64% and turbidity of 60 ± 1.0 NTU led to maximum removal efficiency of 74%. The results of UF experiments showed that UF could not efficiently remove CBZ. Alternatively, UF was more suitable for removing turbidity than MIEX resin. In a separate UF system, the turbidity (20 ± 1.1 NTU) led to a flux reduction of 60% at the first filtration cycle, while the reduction for 1.0 ± 0.1 NTU, 40 ± 1.0 NTU and 60 ± 1.0 NTU were 48%, 52% and 45%, respectively. For the water samples with different turbidities, obvious decrease in membrane fouling was observed after MIEX pretreatment, meanwhile the CBZ/turbidity removal could be improved. The UF membrane was used four times after backwashing to research the reusability of membrane. The integrated processes combining MIEX resin with UF could significantly improve membrane recycling effect and prevent secondary pollution caused by resin., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Based on soluble starch and acrylamide by performing graft polymerization in aqueous solution and hydrolysis step, a low-cost ion exchange resin has been synthesized to remove the heavy metal ions of Cr 3+ and Ni 2+ . The hydrolysis progresses by adding NaOH to convert -CONH 2 to -COONa, and the adsorption experiments confirmed that the functional group to adsorb heavy metals is -COO - , rather than -CONH 2 . During the determination of heavy metal adsorption, the Na + concentration diffused by SR-16 into the solution was also analysed to investigate the ion exchange process. The composition and morphology of SR-16 was characterized by FT-IR, SEM, elemental analyser and EDS, and the results showed that SR-16 has an excellent adsorption capacity to the removal of heavy metal pollution; the adsorption mechanism of SR-16 could be explained by ion exchange progress with -COONa attached on the network structure.

Water pollution is a global problem threatening the entire biosphere and affecting the life of many millions of people around the world. Not only is water pollution one of the foremost global risk factors for illness, diseases and death, but it also contributes to the continuous reduction of the available drinkable water worldwide. Delivering valuable solutions, which are easy to implement and affordable, often remains a challenge. Here we review the current state-of-the-art of available technologies for water purification and discuss their field of application for heavy metal ion removal, as heavy metal ions are the most harmful and widespread contaminants. We consider each technology in the context of sustainability, a largely neglected key factor, which may actually play a pivotal role in the implementation of each technology in real applications, and we introduce a compact index, the Ranking Efficiency Product (REP), to evaluate the efficiency and ease of implementation of the various technologies in this broader perspective. Emerging technologies, for which a detailed quantitative analysis and assessment is not yet possible according to this methodology, either due to scarcity or inhomogeneity of data, are discussed in the final part of the manuscript.

Aggregation is a major concern for therapeutic monoclonal antibody (mAb), as aggregates reduce drug efficacy and safety. In addition to aggregation control, aggregate removal by downstream processing is crucial. Hydrophobic and mixed-mode resins are widely used for aggregate removal in different cases, but they are seldom compared side by side. In this study, the aggregate removing capability of eight resins belonging to different chromatographic types was demonstrated by a case study. This work, by providing multiple options for aggregate removal, allows more flexibility to be gained in downstream processing., (Copyright © 2018 Elsevier Inc. All rights reserved.)

For the early 2000s, chromatographic methods applying chiral stationary phases (CSPs) became the most effective techniques for the resolution of chiral compounds on both analytical and preparative scales. High-performance liquid chromatography (HPLC) employing various types of chiral selectors covalently bonded to silica-based supports offers a state-of-the-art methodology for "chiral analysis." Although a large number of CSPs are available nowadays, the design and development of new "chiral columns" are still needed since it is obvious that in practice one needs a good portfolio of different columns to face the challenging task of enantiomeric resolutions. The development of the unique chiral anion, cation, and zwitterion exchangers achieved by Lindner and his partners serves as an expansion of the range of the efficiently applicable CSPs.In this context this overview chapter discusses and summarizes direct enantiomer separations of chiral acids and ampholytes applying zwitterionic ion exchangers derived from Cinchona alkaloids. Our aim is to provide comprehensive information on practical solutions with focus on the molecular recognition and methodological variables.

This research investigated the removal capacity of polymeric sub-micron ion-exchange resins (SMR) for removal of lead, copper, zinc, and nickel from natural waters in competition with natural organic matter (NOM). Polymeric SMR particles were created and tested to ensure that they were adequately dispersed in the solution. They removed little NOM (10% or less) from river water and wastewater, indicating that competition from NOM was not a major concern. SMR were able to remove 82%±0.2% of lead, 46%±0.6% of copper, 55%±20% of zinc, and 17%±2% of nickel from river water spiked with 500μg/L of each. Similarly, in wastewater, they were able to remove 86%±0.1% of lead, 38%±0.8% of copper, 28%±1% of zinc, and 11%±1% of nickel., (Copyright © 2018. Published by Elsevier B.V.)