High-performance Ion-exchange Research Articles

Microporous Polymer Membranes Enable Efficient Redox Flow Batteries for Energy Storage

Redox flow batteries (RFBs) are promising technologies for grid-scale storage of renewable but intermittent energy sources. RFBs offer superior lifetimes, design modularity and the ability to decouple power from capacity. Ion exchange membranes are critical components in RFBs. Their function is to minimize the crossover of redox active species whilst allowing fast conduction of charge-balancing ions. Perfluorosulfonic acid polymers, such as Nafion, are expensive ($500/m2) and produced using environmentally harmful polyfluoroalkyl substances (PFAS), which is seen as a key limitation in the widespread commercialisation of RFBs.To overcome the challenges of high cost and low ionic selectivity posed by Nafion membranes, we replaced the phenyl groups in poly (ether ether ketone) (PEEK) with the bridged bicyclic triptycene moiety to introduce free-volume into the polymer matrix based on our previous work.1,2 Sulfonated PEEK polymers with triptycene backbones (sPEEK-Trip) were readily cast into mechanically robust membranes. Membrane structural and physical properties were characterized with a variety of techniques, elucidating the changes in water channel morphology. Ionic conductivity and ionic selectivity are critical parameters in flow batteries. Ionic selectivity determines the lifetime of the battery, where capacity is determined by the quanitity of redox species in the respective half-cells. The membranes were used in a range of flow battery chemistries, including aqueous organic flow batteries and alkaline zinc-iron flow batteries. Computational modelling was performed to study the fundamental polymer structures and ion transport mechanism. High ionic conductivity enables low resistance which enables higher efficiencies and cost reductions. However, increasing the ionic conductivity often results in a selectivity penalty owing to higher membrane swelling endowed by the higher hydrophilicity. sPEEK-Trip membranes have higher ionic conductivities (20.1 mS cm-1 vs 10.5 mS cm-1 in 1 M KCl) at the same ion exchange capacity and show no increase in redox species permeability (10-9 cm2 s-1). The measured redox flow battery performance surpasses all reported membranes in a neutral pH aqueous organic and an alkaline zinc-iron system.3 The energy efficiency beyond current densities of 200 mA cm-2 exceeded all reported membranes in the alkaline 2,6-DHAQ AORFB. Furthermore, a power density of 2.5 W cm-2 was achieved in the alkaline zinc-iron system, with an energy efficiency of 62% at current density of 500 mA cm-2. The membrane design will inspire the development of high-performance ion exchange membranes for electrochemical energy storage and conversion.

A readily accessible quaternized cellulose filter paper with high permeability for IgG separation

Anion-exchange chromatography (AEC) is recognized as a highly effective approach for the purification of immunoglobulin G (IgG). This study introduces an innovative strategy that employs waste cellulose filter paper in the production of AEC media. A quaternized cellulose fiber membrane (CFM-QCS) was successfully fabricated that cellulose fibers were as a structural framework, glutaraldehyde (GA) as a crosslinking agent, and quaternary chitosan (QCS) as a modifying agent. Morphological and chemical characterization revealed that GA and QCS were uniformly crosslinked on the surface of the cellulose fibers, resulting in excellent mechanical properties in both dry and wet states. Benefiting from its 3D network scaffold structure, CFM-QCS demonstrated a high adsorption capacity for bovine serum albumin (BSA), with static and dynamic adsorption capacities of 605.15 mg/g and 88.63 mg/ml, respectively. After treated with extreme conditions and 10 cyclic adsorption and elution, the adsorption capacity of CFM-QCS remains almost unchanged, highlighting its excellent stability. Additionally, a CFM-QCS packed chromatography column exhibited high flux of 10.38 L/h at 0.1 MPa, which can efficiently separate IgG from a mixed solution in the presence of BSA and IgG by gravity-driven. This work presents a straightforward approach for preparing high-performance ion-exchange chromatography membranes for IgG separation.

High-performance SPEEK membrane with polydopamine-bridged PTFE nanoparticles for vanadium redox flow batteries

With the growing demand of energy storage techniques in carbon-neutral environments, vanadium redox flow batteries (VRFBs) have emerged as outstanding systems for long-duration energy storage. Developing high-performance ion exchange membrane is essential for broad deployment of RFBs. In this work, a SPEEK/PTFE membrane is designed by incorporating polytetrafluoroethylene (PTFE) nanoparticles into sulfonated poly (ether ether ketone) (SPEEK) membrane by bio-inspired polydopamine (PDA) bridge. PDA combines SPEEK membrane and hydrophobic PTFE nanoparticle tightly by its abundant functional groups. The ion selectivity of optimal SPEEK/PTFE-0.5 % membrane is 8.9 times greater than that of Nafion 115. Remarkably, VRFB with optimal SPEEK/PTFE-0.5 % membrane exhibits excellent battery performances including impressive columbic efficiency (CE, 99.5 %) and energy efficiency (EE, 86.3 %) at 100 mA cm−2 surpassing Nafion 115 (CE, 95.8 %; EE, 83.4 %). Besides, VRFB employing SPEEK/PTFE-0.5 % membrane demonstrates excellent cycling stability, with higher capacity retention (71.4 % after 300 cycles) compared to Nafion 115, indicating its capability of extended operation. This work illustrates that the design of PDA bridge in composite membrane is a useful approach for developing high-performance membranes in RFBs.

Advancing Ion Selective Membranes with Micropore Ion Channels in the Interaction Confinement Regime.

Ion exchange membranes allowing the passage of charge-carrying ions have established their critical role in water, environmental, and energy-relevant applications. The design strategies for high-performance ion exchange membranes have evolved beyond creating microphase-separated membrane morphologies, which include advanced ion exchange membranes to ion-selective membranes. The properties and functions of ion-selective membranes have been repeatedly updated by the emergence of materials with subnanometer-sized pores and the understanding of ion movement under confined micropore ion channels. These research progresses have motivated researchers to consider even greater aims in the field, i.e., replicating the functions of ion channels in living cells with exotic materials or at least targeting fast and ion-specific transmembrane conduction. To help realize such goals, we briefly outline and comment on the fundamentals of rationally designing membrane pore channels for ultrafast and specific ion conduction, pore architecture/chemistry, and membrane materials. Challenges are discussed, and perspectives and outlooks are given.

Efficient separation of uranium and lanthanides based on high-performance ion exchange chromatography

Efficient separation of uranium and lanthanides based on high-performance ion exchange chromatography

A-326 Argininosuccinic Acid - is it Routinely Detectable in the Urine of Healthy Individuals?

Abstract Background Argininosuccinic aciduria is a genetic disorder that results in elevated levels of argininosuccinic acid (ASA) in urine and blood. While there is seemingly a consensus within the clinical literature that any detectable amount of ASA in blood/plasma is diagnostic for argininosuccinic aciduria, yet there is conflict as to whether ASA in urine can be found in unaffected individuals. Some literature states that ASA should not be found in the urine of a healthy individual, while other literature reports low levels of ASA in the urine of healthy individuals. Additionally, many laboratories do not have a normal range for ASA within urine, which implies that any level of ASA found within urine is indicative of argininosuccinic aciduria. This conflict may in part be due to differences in the methods used to determine ASA levels. Newer liquid chromatography tandem mass spectrometry (LCMSMS) methods have been shown to be more sensitive than ion-exchange chromatography (IEC) based amino acid methods for detection of ASA. Additionally, the detection of ASA via IEC requires the heating and acidification of the sample to convert ASA into a single peak for quantitation. Heating and acidification is not routinely done for urine amino acid analysis with IEC; with routine IEC urine amino acid analysis, ASA migrates as three small peaks that may go unnoticed. In our clinical laboratory, which utilizes the less sensitive IEC method, our procedure describes the presence of any ASA in urine as diagnostic for argininosuccinic aciduria. Given the conflicting literature, we set forth to determine whether low levels can be detected in unaffected individuals with an IEC method, and if so, establish a normal range of ASA levels in urine with IEC. Methods Twenty waste urine samples from patients with no prior diagnoses of argininosuccinic aciduria were evaluated. ASA levels within the samples were determined via high performance ion exchange chromatography for separation of compounds followed by derivatization with ninhydrin for spectrophotometric detection with a Hitachi Amino Acid analyzer. The samples were acidified and heated, which converts ASA into a single anhydride peak for accurate quantitation, and the results were normalized to urine creatinine. Results ASA was detected in all twenty urine samples, with an average ASA concentration of 27.2 μmol/g Cr and a range of 11.3–47.7 μmol/g Cr. Conclusion Given these findings, our clinical laboratory procedure has been updated to include the information that ASA can be present in the urine of healthy individuals up to a concentration of 50 μmol/g Cr. Other clinical laboratories that analyze urine to identify argininosuccinic aciduria should be aware of the misinformation in the literature that claims that ASA is not present in the urine of healthy individuals.

Simultaneous determination and distribution analysis of eleven arsenic species in vegetables

A highly sensitive and efficient method for simultaneous determination of arsenic species in vegetables has been developed. Eleven arsenic species were separated and detected using high performance ion exchange chromatography-inductively coupled plasma mass spectrometry (HPIEC-ICP-MS). The extraction efficiency and transformation of arsenic species in vegetables was investigated using five extraction methods and eight solvents. An online background removal technique was firstly established to exclude the influence of environmental arsenic. The gradient elution conditions were optimized and the optimal collision gas velocity for mass spectrometry was determined to be 4 mL min−1 to remove interference by 75ArCl. The detection limits for the method were 0.032–0.12 μg kg−1, and the quantitative limits of the method were 0.10–0.39 μg kg−1. In order to confirm the accuracy and practicability of the method, two food matrix-type certified reference materials were analyzed. The types and concentrations of arsenic species in six different kinds of vegetable were analyzed. The proportions of As (III) and As (V), as well as total arsenic concentrations, were significantly different.

High-capacity/high-rate hybrid column for high-performance ion exchange

Herein, a fixed-bed high-capacity/high-rate (HC/HR) hybrid column was developed using commercial ion-exchange beads (IEBs) and ion-exchange fibers (IEFs). The as-fabricated HC/HR hybrid column exhibited excellent breakthrough bed volume (BV) and utilization efficiency of capacity (UEC) at a high service flow rate (SFR) for the adsorption of Cd(II). The IEBs displayed a high adsorption capacity of 235.2 ± 9.8 mg g−1 and slow adsorption kinetics (k2 = 0.0001 g mg−1 min−1) for the sorption of Cd(II); meanwhile, the IEFs showed a maximum adsorption capacity of only 146.3 ± 7.5 mg g−1, which is lower than that of the IEBs, but fast kinetics (k2 = 0.0130 g mg−1 min−1). At an SFR of 104.23 BV h−1, the HC/HR hybrid column showed excellent performance for the sorption of Cd(II), having a high breakthrough BV of 1009.11 and a UEC of 92.86%; these values are much higher than those of the IEB-packed column. Furthermore, at an increased SFR (318.47 BV h−1), the HC/HR hybrid column maintained its high performance, demonstrating a breakthrough BV of 568.80 and UEC of 83.90%. The regeneration experiment indicates that 97% of the initial capacity was retained. Thus, the HC/HR hybrid column could easily be applied to existing column systems and shows promising performance in ion-exchange processes.

Surface modification, counter-ion exchange effect on thermally annealed sulfonated poly (ether ether ketone) membranes for vanadium redox flow battery

In this work, we report new approaches to sulfonated poly ether ether ketone (SPEEK) membranes to improve its inhibition to vanadium ions along with polymer reinforcement. First approach includes facile thermal annealing of SPEEK membrane (SPEEK-T) which could reinforce the polymer matrix. Second approach was to exchange the labile proton of SPEEK with benzimidazole to protect the hydrolytic decomposition of sulfonic acid followed by thermal annealing (SPEEK-Benz), and third approach focused on creating barrier layer for vanadium ions by coating polyethyleneimine on SPEEK membrane followed by thermal treatment (SPEEK-PEI). The chemical stability study of the membranes revealed acceptable dimension change and VO2+ electrolyte sorption for all the membranes with least dimension change and weight gain of 5 % and 12 %, respectively, for SPEEK-PEI. Amongst four prepared membranes, SPEEK-PEI membrane displayed least diffusion coefficient of 8.04 × 10−7, 8.94 × 10−7, 4.20 × 10−7 cm2 min−1 for V3+, VO2+, and VO2+ ions respectively. VRFB assembled with SPEEK-PEI resulted highest Coulombic efficiency (CE) of 97 % and energy efficiency (EE) of 66 % over 50 charge/discharge cycles at 100 mA cm−2. Peak power density of 255, 248, 240 and 235 mW cm−2 at current density of 300 mA cm−2 was observed for SPEEK-PEI, SPEEK-Benz, SPEEK-T, and SPEEK-48, respectively; these values were higher than 225 mW cm−2 for Nafion®117 in identical experimental conditions. The excellent VRFB performance suggest that the developed new approaches have pronounced effect on the membrane properties and can be further improved to obtain an ideal VRFB separator. Furthermore, the surface modification approaches adopted in this work is facile, reproducible and scalable and can be further designed to develop high performance ion exchange membranes for separation/purification and energy.

Binder effects in photopolymerized acrylate/zeolite composites for 3D printing/ion-exchange applications

In this paper, the influence of permanent binder was first determined on the photopolymerization process under mild condition (visible LED irradiation, at room temperature and under air) of LTA zeolite/polymer based composites. Different inorganic binders were tested in order to investigate their optical properties and to improve the mechanical properties after polymer removal by thermal treatment. Optimum formulation obtained with poly(ethylene glycol) diacrylate (PEGDA) and colloidal silica demonstrates excellent Depth of Cure (DOC) and good spatial resolution. The monolith obtained after thermal treatment at 600 °C shows hierarchical porosity with high BET surface area and high compressive strength. Furthermore, Ni2+ and Sr2+ ion exchange capacities were evaluated and the effect of colloidal silica as binder was investigated. This work extends our understanding of highly-filled composites (solid content up to 60.8 wt% where zeolite content = 40 wt%/21 vol%) obtained by photopolymerization, and expands their applications for 3D printing of high-performance lightweight materials and ion exchange.

Diversity of bacterial community in Jerusalem artichoke (Helianthus tuberosus L.) during storage is associated with the genotype and carbohydrates.

Jerusalem artichoke (JA) is a fructan-accumulating crop that has gained popularity in recent years. The objective of the present study was to determine the dynamics of the JA-microbiome during storage. The microbial population on the surface of the JA tuber was determined by next-generation sequencing of 16S rRNA amplicons. Subsequently, the changes in carbohydrate and degree of polymerization of fructan in tubers during storage were measured. Among different genotypes of JA varieties, intergeneric differences were observed in the diversity and abundance of bacterial communities distributed on the surface of tubers. Additionally, bacterial diversity was significantly higher in storage-tolerant varieties relative to the storage-intolerant varieties. Redundancy analysis (RDA) and the correlation matrix indicated a relationship between changes in the carbohydrates and microbial community succession during tuber storage. The tuber decay rate correlated positively with the degree of polymerization of fructan. Moreover, Dysgonomonas and Acinetobacter in perishable varieties correlated significantly with the decay rate. Therefore, the bacteria associated with the decay rate may be involved in the degradation of the degree of polymerization of fructan. Furthermore, Serratia showed a significant positive correlation with inulin during storage but a negative correlation with the decay rate, suggesting its antagonistic role against pathogenic bacteria on the surface of JA tubers. However, the above correlation was not observed in the storage-tolerant varieties. Functional annotation analysis revealed that storage-tolerant JA varieties maintain tuber quality through enrichment of biocontrol bacteria, including Flavobacterium, Sphingobacterium, and Staphylococcus to resist pathogens. These results suggested that crop genotype and the structural composition of carbohydrates may result in differential selective enrichment effects of microbial communities on the surface of JA varieties. In this study, the relationship between microbial community succession and changes in tuber carbohydrates during JA storage was revealed for the first time through the combination of high-throughput sequencing, high-performance liquid chromatography (HPLC), and high-performance ion-exchange chromatography (HPIC). Overall, the findings of this study are expected to provide new insights into the dynamics of microbial-crop interactions during storage.

Pourbaix Diagram of Astatine Revisited: Experimental Investigations.

The Pourbaix diagram of an element displays its stable chemical forms with respect to the redox potential and pH of the solution, whose knowledge is fundamental for understanding and anticipating the chemistry of the element in a specified solution. Unlike most halogens, the Pourbaix diagram in the aqueous phase for astatine (At, Z = 85) is still under construction. In particular, the predominant domains of two astatine species assumed to exist under alkaline conditions, At- and AtO(OH)2-, need to be refined. Through high-performance ion-exchange chromatography, electromobility measurements, and competition experiments, the existence of At- and AtO(OH)2- has been confirmed and the associated standard potential has been determined for the first time (0.86 ± 0.05 V vs the standard hydrogen electrode). On the basis of these results, a revised version of astatine's Pourbaix diagram is proposed, covering the three oxidation states of astatine that exist in the thermodynamic stability range of water: At(-I), At(I), and At(III) (as At-, At+, AtO+, AtO(OH), and AtO(OH)2-).

Pasting Properties of Various Waxy Rice Flours: Effect of α-Amylase Activity, Protein, and Amylopectin

Waxy rice has a long history of being cultivated and consumed in China. In this study, the effect of different factors including α-amylase activity, protein, and amylopectin structure on the pasting properties of four waxy rice varieties were investigated. Rice flours were divided into four groups (Vietnam indica (VI), Jiangxi indica (JI), Anhui japonica (AJ), and Dongbei japonica (DJ) group) and treated with AgNO3 solution, DL-dithiothreitol (DTT), or protease (n = 3). Results suggested that both α-amylase activity and protein significantly decrease the pasting viscosity of waxy rice flours. Chain length distribution of amylopectin as measured by high performance ion exchange chromatography (HPAEC-PAD) showed that starch with a higher ratio of short chain leads to a higher pasting viscosity. X-Ray diffractograms showed that the crystal type of all the four varieties of rice starches were characteristic A-type. Relative crystallinity of each rice starch was further calculated, and higher crystallization resulted in a higher viscosity. Our study would provide a fundamental knowledge of the relationship between different factors and waxy starch pasting properties, as well as be a reference for controlling the quality of waxy rice starch-based food products.

High proton selectivity membrane based on the keto-linked cationic covalent organic framework for acid recovery

The cationic covalent organic frameworks (COFs) with editable pore environment and pore size are promising candidates for constructing the ion channel of anion exchange membranes (AEMs) with excellent separation properties, but the high reversible linking bond (e.g. imine) makes these membranes unstable in the industrial applications. In this work, the keto-linked COF (TpTGCl) with high acid-stability was fabricated on the surface of carboxyl-modified polyacrylonitrile (CPAN) ultrafiltration membrane. The COF active layer with positively charged property in pore channels afforded high separation factor of H+/Fe2+ up to 450 under batch dialysis process. Owing to the electrostatic repulsion, the cationic nanopore demonstrated a screening feature that transmitted H+ and rejected Fe2+. Moreover, the membranes (TpTGCl/CPAN) exhibited outstanding acid-stability, which could maintain high separation performance after 10 cycle under strong-acid conditions. The result suggested that COF with chemical stability and functional embellishment offered opportunities to synthesis high performance ion exchange membrane, and it could further be leveraged to tackle other challenges in membrane separation field.

Undeclared (Poly)phosphates Detection in Food of Animal Origin as a Potential Tool toward Fraud Prevention

(Poly)phosphates are approved as water-preserving and emulsifying agents that improve the appearance and consistency of many food products. The labelling of added (poly)phosphates is essential for protecting vulnerable population groups and to prevent unfair trade practices resulting in economic fraud. The problems with (poly)phosphates’ utilisation concerns both analytical and legislative issues, such as: (1) their straightforward detection; (2) excessive addition altering freshness perception and misleading consumers; (3) uncontrolled usage increasing foodstuff weight; (4) application in products where they are not permitted; and (5) no indication on the label. Bearing all these issues in mind, the main purpose of this study was the quantification and screening of the (poly)phosphates profile in meat, marine and dairy products (160 samples), of which 43 were without declared (poly)phosphate treatment. Analysis was completed by high-performance ion-exchange chromatography either with conductometric detection or coupled to Q-Exactive Orbitrap high-resolution mass spectrometry. Although the (poly)phosphates profiles varied greatly according to species and processing type, the following criteria for detection of illicit treatment were established: high orthophosphate level, quantified short-chain (poly)phosphate anions and the presence of long-chain forms. In conclusion, the instrumental platforms used in this study can be recommended to inspection bodies as reliable methods for the detection of food adulteration with (poly)phosphates.

Adsorption and purification performance of lysozyme from chicken egg white using ion exchange nanofiber membrane modified by ethylene diamine and bromoacetic acid

A high-performance polyacid ion exchange (IEX) nanofiber membrane was used in membrane chromatography for the recovery of lysozyme from chicken egg white (CEW). The polyacid IEX nanofiber membrane (P-BrA) was prepared by the functionalization of polyacrylonitrile (PAN) nanofiber membrane with ethylene diamine (EDA) and bromoacetic acid (BrA). The adsorption performance of P-BrA was evaluated under various operating conditions using Pall filter holder. The results showed that optimal conditions of IEX membrane chromatography for lysozyme adsorption were 10% (w/v) of CEW, pH 9 and 0.1 mL/min. The purification factor and yield of lysozyme were 402 and 91%, respectively. The adsorption process was further scaled up to a larger loading volume, and the purification performance was found to be consistent. Furthermore, the regeneration of IEX nanofiber membrane was achieved under mild conditions. The adsorption process was repeated for five times and the adsorption capacity of adsorber was found to be unaffected.

Advanced Nafion hybrid membranes with fast proton transport channels toward high-performance vanadium redox flow battery

The development of high-performance ion exchange membranes to break the trade-off between ion selectivity and conductivity is always a great challenge for the vanadium redox flow battery (VRFB). Herein, a hybrid membrane was successfully prepared via the solution casting method. The UiO-66-SO3H was embedded in Nafion matrix, acting as an effective barrier for vanadium ions to realize enhanced ion selectivity. At the same time, besides the intrinsic proton cluster channels in Nafion, two types of additional proton transport channels formed in the membranes, which further improved the conductivity of the membranes. Consequently, the VRFB with an optimized hybrid membrane exhibited enhanced voltage efficiency (VEs: 91.5-78.4%) and outstanding energy efficiency (EEs: 86.0-76.1%) compared with the one with recasting Nafion membrane (rNf) (VEs: 86.9-69.0%, EEs: 80.3-66.0%) at 80–220 mA cm-2. The efficiency kept stable for 1000 cycles in the long-term cycling tests, and the discharge capacity decay rate of the VRFB with the hybrid membrane is only 0.13% per cycle, which is in obvious contrast to the one with rNf (0.73% per cycle). In addition, the electrolyte utilization rate of the VRFB assembled with the hybrid membrane was much higher than that of the one with rNf.

Assessment of Diadenylate Cyclase and c-di-AMP-phosphodiesterase Activities Using Thin-layer and Ion Exchange Chromatography.

All living cells use cyclic nucleotides as second messengers for signal sensing and transduction. Cyclic di-3',5'-adenosine monophosphate (c-di-AMP) is primarily involved in the control of bacterial and euryarcheal osmoadaptation and is produced by diadenylate cyclases from two molecules of ATP. Specific phosphodiesterases hydrolyze c-di-AMP to the linear phosphoadenylate adenosine 5'-pApA or to AMP. Different methods including high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC) and ion exchange chromatography (IEX) can be used to determine activities of c-di-AMP-synthesizing and degrading enzymes. Here, we describe in detail the TLC and IEX methods adapted for characterization of the diadenylate cyclase DisA and the phosphodiesterase AtaC from Streptomyces venezuelae. TLC allows quick and easy separation of radioactive-labeled substrates and products, while IEX avoids utilization of potentially hazardous radioactive substrates and can be used as a good substitute if an HPLC system is not available. Unlike in TLC assays, samples cannot be analyzed in parallel by using the IEX assay, thus it is more time consuming.

Comparison of Novel 1,1-Diphenylethylene Alternating Copolymer and Polystyrene Based Anion Exchange Membranes

This research investigates 1,1-diphenylethylene as a monomer in polymeric ion exchange membranes through the synthesis of a novel alternating copolymer functionalized for ion transport and analysis of mechanical and conductive properties. This will further the development of cost effective and high-performance ion exchange membranes, enabling energy systems that employ ion-transporting membranes, like fuel cells and electrolyzers, to become more economically viable, which in turn would lead to cleaner and more sustainable energy production.The goal of the project is to develop an understanding of chemical structure-physical property relationships to make self-assembling ion-conducting channels in ionomers which have physical properties that prevent the excess swelling that leads to the mechanical failure of membranes. In this vein, anion exchange membranes (AEMs) based on 1,1-diphenylethylene were synthesized and their ion conducting properties and physical state were characterized. Poly(1,1-diphenylethylene-alt-butadiene) alternating copolymer was synthesized via anionic polymerization, then selectively hydrogenated to eliminate double bonds in the polymer backbone. The pendant aromatic rings of the selectively hydrogenated poly(1,1-diphenylethylene-alt-butadiene) were then subjected to quantitatively controlled functionalized by super acid catalyzed Friedel-Crafts bromoalkylation, then aminated with trimethylamine. AEMs spanning a wide range of ion exchange capacities (IECs), 0.39-1.99 milliequiv./gram (meq./g), were made. Conductivity increased with IEC and temperature. Polystyrene based AEMs of similar IECs, 0.38-2.14 meq/g, were synthesized as a standard to compare the 1,1-diphenylethylene based copolymers. The 1,1-diphenylethylene based copolymers had favorable conductivities compared to polystyrene membranes of similar IEC. The glass transition temperature, water uptake, and dimensional swelling were investigated to explain the difference in conductivities between the two species. Figure 1

Detection of polyphosphates in seafood and its relevance toward food safety.

Polyphosphates are permitted as food additives (Regulation EC No 1129/2011) but their undeclared utilisation is considered fraudulent. They improve water holding capacity of the seafood, preventing biochemical/physical changes during commercialization. The key objective of this study was the detection of polyphosphate in various seafood categories, by means of high-performance ion-exchange chromatography with suppressed conductometry (HPIEC-SCD) coupled to Q-Exactive Orbitrap high resolution mass spectrometry (HRMS-Orbitrap). Ten frozen cuttlefish samples did not reveal any treatment, while in ten frigate tunas, high concentration of orthophospate was found. Unambiguous hexametaphosphate presence was demonstrated in four prawn samples, while triphosphate was quantified (11.2±4 ug/g) in another four prawn samples that contained orthophosphate (10225±1102 ug/g), as well. Other samples sporadically encompassed polyphosphates profiles that varied according species and processing type. This analytical approach provided sustenance in better understanding regarding utilization of polyphosphates through HRMS fingerprinting of anionic species that would be specific in food safety control.