Resin Gel Research Articles

Investigating the loss of an embedded perfluorinated optical fiber for different resin’s gel time

This work aims to find out the gel time that may not cause damage to the physical properties of the polymer optic fiber (POF). Effect of gel time of vinylester resin on signal attenuation of POF was studied. The resin gel time was controlled by mixing different ratios of Methylethylketone peroxide (MEKP), Cobalt Naphthenate-6 %, and Dimethylaniline at 18 °C. OTDR was used to measure backscattering level and signal loss during the resin curing process. Optical imaging was conducted on POF cross section before and after resin treatment to investigate the effect of resin gel time on its physical properties. Results showed that POF signal was affected by resin gel time. Increasing gel time caused drop of the backscattering level of the POF. It was found that 15 minutes gel time had no significant effect on POF signal integrity. Gel time 45 minutes or longer cause severe physical damage to the POF.

Evaluation and application of Diffusive Gradients in Thin Films (DGT) technique using Chelex®-100, Metsorb™ and Diphonix® binding phases in uranium mining environments

A new resin- Diphonix® in Diffusive Gradients in Thin Films (DGT) technique for the determination of uranium was investigated and compared with previously used binding phases for uranium, Chelex®-100 and Metsorb™. The DGT gel preparation and the elution procedure were optimized for the new resin. The U uptake on Diphonix® resin gel was 97.4 ± 1.5% (batch method; [U] = 20 μg L−1; 0.01 M NaNO3; pH = 7.0 ± 0.2). The optimal eluent was found to be 1 M 1-hydroxyethane-1, 1-diphosphonic acid (HEDPA) with an elution efficiency of 80 ± 4.2%. Laboratory DGT study on U accumulation using a DGT samplers with Diphonix® resin showed a very good performance across a wide range of pH (3–9) and ionic strength (0.001–0.7 M NaNO3). Diffusion coefficients of uranium at different pH were determined using both, a diffusion cell and the DGT time-series, demonstrating the necessity of the implementation of the effective diffusion coefficients into U-DGT calculations. Diphonix® resin gel exhibits greater U capacity than Chelex®-100 and Metsorb™ binding phase gels (a Diphonix® gel disc is not saturated, even with loading of 10.5 μmol U). Possible interferences with Ca2+ (up to 1.33 × 10−2 M), PO43− (up to 1.72 × 10−4 M), SO42− (up to 4.44 × 10−3 M) and HCO3− (up to 8.20 × 10−3 M) on U-DGT uptake ([U] = 20 μg L−1) were investigated. No effect or minor effect of Ca2+, PO43−, SO42−, and HCO3− on the quantitative measurement of U by Diphonix®-DGT was observed. The results of this study demonstrated the DGT technique with Diphonix® resin is a reliable and robust method for the measurement of labile uranium species under laboratory conditions.

The effect of graphene oxide (GO) nanoparticles on the processing of epoxy/glass fiber composites using resin infusion

In this paper, the effects of graphene oxide (GO) nanoparticles on glass fiber composite processing by incorporating them into epoxy resin were investigated. GO was synthesized from graphite powder and was mixed with epoxy resin. Three different GO contents of 0.05, 0.1, and 0.2 wt% were used. Epoxy/GO samples were tested for rheology and cure kinetics to evaluate the effects of GO content on important resin infusion processing parameters. The results show that adding GO to neat epoxy resin increased the viscosity and affected the resin cure reaction by reducing the resin gel time. After that, glass fiber composites were prepared using the resin infusion process. Samples with 0.2 wt% GO result in very slow resin infiltration time with premature resin gelation. A 30 % increase in flexural strength and a 21 % increase in flexural modulus are manifested by adding GO as the secondary reinforcement to glass fiber composites.

Preparation and toxicological evaluation of methyl pyranoanthocyanin

Anthocyanins are increasingly valued in the food industry for their functional properties and as food colorants. The broadness of their applications has, however, been limited by the lack of stability of these natural pigment extracts in a number of food systems. The potential application of pyranoanthocyanins, anthocyanin derivatives with better stability conferred by the added pyran ring, as a food ingredient was determined. Methylpyranoanthocyanin (MPA) was prepared from reaction of acetone and anthocyanin extracts from red grapes. Reaction products were sequentially purified with polyamide resin, TSK gel resin and semi-preparative HPLC to a purity level >98%. Cytoprotective influence tests of the purified MPA indicated its significant protective effect against H2O2 induced MRC-5 cell damage. Results of evaluations of possible acute toxicity effects on MPA-fed mice, including macro and microscopic assessments, support the conclusion of a non-toxic effect of MPA, and its potential safe use as a food additive.

Isolation and identification of antiproliferative substances from ginseng fermented using Ganoderma lucidum mycelia

Two active substances from ginseng fermented using Ganoderma lucidum mycelia were investigated for antiproliferative effects against the human lung cancer cell line A549. The chloroform fraction of fermented ginseng extracts showed a strong antiproliferative effect. This fraction was isolated and purified using silica gel and C18 resin column chromatography and semi-preparative reverse phase HPLC. The structures of isolated compounds were determined using spectroscopic methods (ESI-MS, 1H and 13C NMR). Isolated compounds were identified as ginsenoside compound K and 3-oxo-compound K. Both inhibited A549 cell growth in a dose-dependent manner. Cell viability values for ginsenoside compound K were 74.88, 59.30, 5.76, 5.79, and 6.27% at 6.25, 12.50, 25.00, 50.00, and 100.00 μg/mL, respectively, and ginsenoside 3-oxo-compound K showed values 89.40, 59.62, 6.05, and 4.64% at 3.70, 7.50, 15.00, and 30.00 μg/mL, respectively. Compound K and 3-oxo-compound K from fermented ginseng can be used as natural anti-cancer agents.

Prolongation of curing of epoxy-novolac vinyl ester resin with transition metal acetylacetonates

The effect of transition metal (Fe, Cu, Co, Ni, Cr, Mn) acetylacetonates on curing of epoxy-novolac vinyl ester resin was studied. The resin gel time was determined by the method for monitoring gelation of liquids with increased viscosity, and the influence of the structure and concentration of metal acetylacetonates on the process was examined. Nickel acetylacetonate inhibits the curing, whereas cobalt acetylacetonate ensures relatively fast process completion and can be used as curing accelerator. Iron and chromium acetylacetonates prolong the process. The curing time can be regulated by varying the amount of the additive.

A novel and effective chromatographic approach to the separation of isoflavone derivatives from Pueraria lobata.

A novel and effective chromatographic approach to the separation and purification of isoflavone compounds from Pueraria lobata is described. The method is based on flash chromatography (FC), coupled to preparative high performance liquid chromatography (prep-HPLC) via a six-way valve. The FC step comprised tandem reversed phase columns, pre-packed with MCI gel (Mitsubishi Chemical Corp., Tokyo, Japan) and C18 (Fuji Silysia Chemical Ltd, Osaka, Japan) resin, respectively, and was designed to separate a crude Pueraria lobata extract into several preliminary fractions. Fractions containing the target compounds were then directly injected via the six-way valve into prep-HPLC columns, without further treatment, for final isolation and purification. Nine isoflavonoids were successfully isolated, three through an online mode and the other six through an offline mode. The purities of all compounds exceeded 95.0%, as determined by HPLC with an UV-vis photodiode array detector. The convenience, low solvent consumption, and time-saving advantages of this method offer an attractive and promising approach to the isolation of natural products.

Determination of mercury species by the diffusive gradient in thin film technique and liquid chromatography – atomic fluorescence spectrometry after microwave extraction

A diffusive gradient in thin films technique (DGT) was combined with liquid chromatography (LC) and cold vapor atomic fluorescence spectrometry (CV-AFS) for the simultaneous quantification of four mercury species (Hg2+, CH3Hg+, C2H5Hg+, and C6H5Hg+). After diffusion through an agarose diffusive layer, the mercury species were accumulated in resin gels containing thiol-functionalized ion-exchange resins (Duolite GT73, and Ambersep GT74). A microwave-assisted extraction (MAE) in the presence of 6M HCl and 5M HCl (55°C, 15min) was used for isolation of mercury species from Ambersep and Duolite resin gels, respectively. The extraction efficiency was higher than 95.0% (RSD 3.5%). The mercury species were separated with a mobile phase containing 6.2% methanol+0.05% 2-mercaptoethanol+0.02M ammonium acetate with a stepwise increase of methanol content up to 80% in the 16th min on a Zorbax C18 reverse phase column. The LODs of DGT–MAE–LC–CV-AFS method were 38ngL−1 for CH3Hg+, 13ngL−1 for Hg2+, 34ngL−1 for C2H5Hg+ and 30ngL−1 for C6H5Hg+ for 24h DGT accumulation at 25°C.

General and Straightforward Synthetic Route to Phenolic Resin Gels Templated by Chitosan Networks

General and Straightforward Synthetic Route to Phenolic Resin Gels Templated by Chitosan Networks

Chemical Constituents of the Roots of Trichosanthes kirilowii

The genus Trichosanthes Linn. (Cucurbitaceae) is composed of about 50 species distributed mainly in Southeast Asia. In traditional Chinese medicine the roots of Trichosanthes kirilowii Maxim., commonly known as “Tian Hua Fen,” are used for the treatment of cough, inflammation, polydipsia, and diabetes [1]. Most previous phytochemical studies of T. kirilowii have focused on the fruits and seeds, and triterpenoids, sterols, amino acid, lipids, and other compounds have been isolated from different parts of the plant [2–5]. In our research on chemical constituents of the roots of T. kirilowii, which has rarely been reported in recent years, 18 compounds were isolated and elucidated as 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid (1), allantoin (2), nicotinic acid (3), xanthine (4), adenine (5), uracil (6), thymine (7), guanosine (8), uridine (9), phenylalanine (10), tyrosine (11), 1-C-(p-hydroxyphenyl)-glycerol (12), furoic acid (13), p-hydroxybenzoic acid (14), p-hydroxybenzaldehyde (15), succinic acid (16), -spinasterol-3-O-D-glucopyranoside-6 -O-palmitate (17), and bryonolic acid (18). Plant Material. The roots of Trichosanthes kirilowii were collected from Hebei Province of China in July 2010 and authenticated by Prof. Tian-Xiang Li, Tianjin University of Traditional Chinese Medicine. A voucher specimen was deposited in the herbarium of pharmacognosy, Tianjin University of Traditional Chinese Medicine. Extraction and Isolation. The air-dried roots (14 kg) were cut into small pieces and refluxed with 95% EtOH and then with 50% EtOH twice. The extract was suspended in water and successively partitioned with petroleum ether (60–90 C), CH2Cl2, EtOAc, and n-BuOH in turn. The petroleum ether extract (45 g) was subjected to silica gel column chromatography eluting with petroleum ether–EtOAc in a gradient manner, and further purified by silica gel and Sephadex LH-20 column chromatography repeatedly to afford compounds 17 (80 mg) and 18 (25 mg). The CH2Cl2 extract (30 g) was subjected to silica gel column chromatography eluting with gradient CH2Cl2–EtOAc to get compounds 12 (8 mg) and 15 (6 mg). The EtOAc extract (18 g) was repeatedly separated by silica gel, Sephadex LH-20, and preparative TLC to yield compounds 2 (85 mg), 3 (5 mg), 4 (5 mg), 6 (72 mg), 9 (3 mg), 13 (7 mg), 14 (15 mg), and 16 (100 mg). The n-BuOH extract (170 g) was chromatographed over a D101 macroporous resin column eluting with H2O and 30%, 50%, 70%, and 95% EtOH. The 30% eluate (37 g) was subjected to silica gel column chromatography and further purified on Sephadex LH-20 and ODS columns to give compounds 1 (20 mg), 5 (20 mg), 7 (3 mg), 8 (150 mg), 10 (80 mg), and 11 (8 mg). The structures of the compounds were identified by a combination of spectroscopic methods (MS, 1H NMR, and 13C NMR) and physicochemical properties. The spectroscopic data of all the compounds were in good agreement with the literature data. 1H and 13C NMR spectra were recorded on 400 MHz and 600 MHz Bruker AV III spectrometers (Bruker, Switzerland). ESI-MS data were obtained on a Waters Quattro Premier XE mass spectrometer (Waters, USA). Silica gel (100–200 and 200–300 mesh, Qingdao Haiyang Chemical Co. Ltd., China), Sephadex LH-20 gel (GE Healthcare Bio-Sciences AB, Sweden), ODS (YMC Co. Ltd, Japan), and D101 resin (Tianjin Haiguang Chemical Co. Ltd., China) were used for column chromatography. TLC was carried out using precoated plates with GF254 silica gel (Qingdao Haiyang Chemical Co. Ltd., China). Spots on TLC were visually observed under UV light and by spraying with 5% H2SO4 reagent followed by heating.

Application of the diffusive gradients in thin films technique for available potassium measurement in agricultural soils: Effects of competing cations on potassium uptake by the resin gel

The utilization of Amberlite (IRP-69 ion-exchange resin, 100–500 wet mesh) as the binding phase in the diffusive gradients in thin films (DGT) technique has shown potential to improve the assessment of plant-available K in soils. The binding phase has recently been optimized by using a mixed Amberlite and ferrihydrite (MAF) gel which results in linear K uptake over extended deployment periods and in solutions with higher K concentrations. As restriction of K uptake by Ca on the Amberlite based resin gel has been previously proposed, potential competing effects of Ca2+, Mg2+ and NH4+ on K uptake by the MAF gel were investigated. These cations had no effect on K elution efficiency which was 85%. However, K uptake by the MAF gel was restricted in the presence of competing cations in solution. Consequently, the diffusion coefficient of K decreased in the presence of cations compared to previous studies but was stable at 1.12×10−5cm2s−1 at 25°C regardless of cation concentrations. Uptake of K by the DGT device was affected by the presence of excessive Ca in more than 30% of twenty typical Australian agricultural soils. However, this problem could be circumvented by using a shorter deployment time than the normal 24h. Moderate correlation of concentrations of K extracted by DGT with Colwell K (extracted by NaHCO3, R2=0.69) and NH4OAc K (R2=0.61) indicates that DGT measures a different pool of K in soils than that measured by the standard extractants used. In addition, the MAF gel has the ability to measure Ca and Mg simultaneously.

Comparison of different types of diffusive gradient in thin film samplers for measurement of dissolved methylmercury in freshwaters

Determination of bioavailable concentrations of methylmercury (MeHg+) in freshwater is key to further understanding its potential risk and toxicity. In this work, two in-house-manufactured mercury-specific diffusive gradients in thin films (DGT) were used in laboratory to assess the lability of MeHg+, and to develop a relationship between chemical lability and bioavailability. After diffusing through the diffusive gel, the MeHg+ accumulated in a thiol functionalised resin gel was extracted using acidic thiourea that was analysed using aqueous-phase propylation followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography (GC) coupled to pyrolysis-atomic fluorescence spectrometry (Py-AFS) detection. The diffusion coefficient (D) at 25°C in agarose (A-DGT) in the absence and presence of dissolved organic matter (DOM) was obtained. Moreover, these values were experimentally compared against polyacrylamide (P-DGT), which is the most frequently used DGT for mercury to date. Statistically significant differences were observed between D values for A-DGT in the absence (3.15×10−6cm2s−1) and presence of DOM (2.68×10−6cm2s−1) and also for P-DGT (2.49×10−6 and 1.69×10−6cm2s−1). Interestingly, our results show that diffusion of MeHg+ was higher on agarose diffusive gel with and without DOM in comparison with those observed in polyacrylamide. Even with higher diffusion coefficients of MeHg+ in the agarose diffusion layer, however, DGT based on polyacrylamide seems to be a better choice for eutrophic waters, when monitoring very low concentrations of MeHg+, considering its slightly higher uptake capacity.

Gelation Performance and Microstructure Study of Chromium Gel and Phenolic Resin Gel in Bulk and Porous Media

Polymer gel has been widely used to control excessive water production in many mature oilfields; however, there still exist some problems concerning the differences between gelation behavior in bulk and porous media. In this paper, the gelation time and microstructures of chromium gel and phenolic resin gel in bulk and porous media were studied. Results showed that for chromium gel, the initial gelation time in porous media was about 2.5–3.5 times of that in bulk and final gelation time in porous media was about 6.0–7.0 times of that in bulk. While for phenolic resin gel, the initial gelation time in porous media was about 1.0–1.5 times of that in bulk, and final gelation time in porous media was about 1.5–2.0 times of that in bulk. The morphology of chromium gel and phenolic resin gel in bulk were dendritic shape structure and 3D network structure, respectively. However, the morphology of chromium gel and phenolic resin gel in porous media were both dense gel membranes at low magnification. While at higher magnification, compared with the branchlike cluster structure of chromium gel in porous media, the network of phenolic resin gel was more developed. The experimental results can provide the basis for determining well shut off time and reveal the differences of gel microstructures between the chromium gel and phenolic gel in bulk and porous media.

Removal of tartaric acid by gel and macroporous ion-exchange resins

The objective of this study is to investigate the removal efficiency of tartaric acid from aqueous solution and wine waste by gel and macroporous ion-exchange resins. The resin amount and pH have an important effect on the removal rate. The maximum removal of tartaric acid was achieved at pH ≥ 4. Tartaric acid adsorption isotherms were analyzed using Langmuir and Freundlich models. The results obtained have shown that Langmuir model fits well for both resins. Sorption kinetics for these resins fit to Ho pseudo-second-order kinetics model. The hybrid precipitation-cation exchange resin system was used for recovery of tartaric acid from liquid wine wastes. The obtained results showed that hybrid system can be used as an alternative method for the recovery of tartaric acid. The 90% of tartaric acid was recovered by hybrid system.

Determination of Dynamic Metal Complexes and their Diffusion Coefficients in the Presence of Different Humic Substances by Combining Two Analytical Techniques

The combined use of a competing ligand exchange (CLE) method and a diffusive gradient in thin films (DGT) technique in a quasi-labile system provides a better understanding of dynamic metal (Cu and Ni) complexes in the presence of humic substances of different origins. The CLE and DGT techniques provide total labile (dynamic) metal complexes (Cu and Ni) and their dissociation rate constants in environmental systems. DGT was found to estimate lower concentrations of labile metal complexes than CLE. These discrepancies were caused by diffusion controlled metal flux (towards the binding resin gel) in the diffusive gel of DGT. The interactions of Cu and Ni with humic acids are stronger than their interactions with fulvic acid and natural organic matter. Changes in the lability of Ni and Cu complexes (complexed with humic substances of different origins) with the changing analytical detection window indicate that the complexes of these metals were formed with different binding sites with diverse binding energies in the humic substances. The combination of these two techniques was found to be very useful in determining diffusion coefficients of labile metal-humate complexes in quasi-labile systems. The values of diffusion coefficients of labile Ni and Cu complexes determined in this study are in good agreement with limited results from the literature. This finding is novel and can be very useful in further improving our understanding of the metal-humate interactions in natural environments.

Development of the diffusive gradient in thin films technique for the measurement of labile mercury species in waters

The diffusive gradients in thin films (DGT) technique, utilizing resin gel with ion-exchange resin Duolite GT73 and new ion-exchange resin Ambersep GT74, was investigated for the accumulation of four mercury species (Hg2+, CH3Hg+, C2H5Hg+, C6H5Hg+). The diffusion coefficients of mercury species in agarose gel calculated on the basis of Fick’s Law were mercury species-specific. The diffusion coefficients of Hg2+ and CH3Hg+ at 25°C (9.07±0.23×10−6cm2s−1 and 9.06±0.30×10−6cm2s−1, respectively) were very similar, but the diffusion coefficients of C2H5Hg+ (6.87±0.23×10−6cm2s−1) and C6H5Hg+ (3.86±0.19×10−6cm2s−1) were significantly lower. Influence of experimental conditions (pH, selected cations, chlorides and humic substance) on mercury species accumulation by DGT was studied. The DGT technique was applied to river water spiked with mercury species.

Kinetic Study of Acetic Acid Esterification with Methanol Catalyzed by Gel and Macroporous Resins

The liquid-phase acetic acid esterification kinetics with methanol to methyl acetate and water catalyzed by gel (Lewatit K1221) and macroporous (Lewatit K2629) ion exchange resins have been investigated and compared with literature reported data acquired on Amberlyst 15. The effects of the resin swelling, the initial molar methanol to acetic acid ratio (1:1 – 10:1) and the temperature (303 – 333 K) on the reaction kinetics were investigated. The gel type resin exhibits a remarkably higher catalytic activity compared to the macroporous resins, despite its similar number of sulfonic acid groups. This can be attributed to the differences in active site accessibility during reaction and, hence, in resin swelling, especially when it is in contact with polar components, such as water and methanol. The differences in catalytic behavior between the considered resins have been assessed using an exchange based Eley-Rideal model in which it is assumed that (1) all the active sites are occupied, (2) the acid undergoes a proton exchange with the protonated methanol and (3) the reaction occurs according to an Eley-Rideal mechanism with the surface reaction between protonated acetic acid and methanol from the bulk as ratedetermining step. This model, which implicitly accounts for resin swelling, could describe the observed differences between the various resins. The activation energy was determined at 47 kJ mol−1, irrespective of the resin used.

Ion-exchange resin catalyzed transesterification of ethyl acetate with methanol: Gel versus macroporous resins

The liquid-phase transesterification kinetics of ethyl acetate with methanol to ethanol and methyl acetate catalyzed by gel (Lewatit K1221) and macroporous (Lewatit K2640, Lewatit K2629 and Amberlyst 15) ion-exchange resins have been investigated. The effects of the resins’ swelling, the initial reactant molar ratio (1:1–10:1) and the temperature (303.15–333.15K) on the reaction kinetics were assessed. Macroporous Lewatit K2629, Lewatit K2640 and Amberlyst 15 exhibit a clearly inferior catalytic activity compared to the gel type Lewatit K1221, despite the similar number of sulfonic acid active sites. This trend in catalytic activity can be explained by the differences in acid site accessibility, which are related to the resins’ swelling behavior and, hence, the extent of divinylbenzene cross-linking in the polymeric structure. A fundamental kinetic model, accounting for the chemical elementary steps as well as for the physical swelling due to solvent sorption, was constructed. According to this model (1) all active sites are initially occupied by protonated methanol, (2) the esters are activated by a proton exchange with protonated methanol and (3) the reaction occurs through an Eley–Rideal mechanism with the surface reaction of protonated ethyl acetate with methanol from the bulk as the rate-determining step. The kinetic model adequately described the experimental data as a function of temperature, initial molar ratio and catalyst resin type. A value of 49kJmol−1 was obtained for the activation energy, irrespective of the resin used. Differences in catalytic activity caused by the accessibility of the active sites are reflected by the values obtained for the reaction rate coefficient, which is 3–4-fold higher for a gel type resin compared to the macroporous ones.

A novel method for the determination of dissolved methylmercury concentrations using diffusive gradients in thin films technique

A novel DGT probe and analysis protocol were developed for the determination of MeHg concentrations in aquatic system. The DGT probe consisted of an agarose (AG) gel as the diffusive hydrogel and a 3-mercaptoproply functionalised silica resin gel as the resin gel. The polyacrylamide (PA) hydrogel which is commonly used in DGT probes to assess trace metal concentrations in aquatic system appeared to be unsuitable for the determination of MeHg. The affinity of the PA hydrogel for MeHg is very high reducing its accumulation by the resin. In contrast, the AG hydrogel presents a by far lower affinity towards MeHg, which makes it suitable as diffusive layer in a DGT probe for MeHg determinations. Two extraction procedures to liberate MeHg from the resin were studied: one is involving thiourea as complexing agent, the other a simple acidic extraction. The extraction step was followed by an ethylation reaction of the liberated MeHg to determine low concentrations of MeHg species by Headspace-Gas Chromatography-Atomic Fluorescence (HS-GC-AFS). With the thiourea extraction method the recovery of the adsorbed MeHg compounds was extremely low while the recovery with the acid extraction method was 100%. The reliability of the novel DGT probe and analysis protocol was studied. A linear dependency between the amount of MeHg accumulated on the resin gel and both the deployment time and the gel thickness were demonstrated. From those experiments a diffusion coefficient of MeHg in AG gel was determined: 5.1±0.20×10(-6) cm(2) s(-1). Additional experiments showed that the new DGT method can be used in most natural waters independent of the ionic strength and within a pH range of 3-8.

Simple Method for Shiga Toxin 2e Purification by Affinity Chromatography via Binding to the Divinyl Sulfone Group

Here we describe a simple affinity purification method for Shiga toxin 2e (Stx2e), a major causative factor of edema disease in swine. Escherichia coli strain MV1184 transformed with the expression plasmid pBSK-Stx2e produced Stx2e when cultivated in CAYE broth containing lincomycin. Stx2e bound to commercial D-galactose gel, containing α-D-galactose immobilized on agarose resin via a divinyl sulfone linker, and was eluted with phosphate-buffered saline containing 4.5 M MgCl2. A small amount of Stx2e bound to another commercial α-galactose-immobilized agarose resin, but not to β-galactose-immobilized resin. In addition, Stx2e bound to thiophilic adsorbent resin containing β-mercaptoethanol immobilized on agarose resin via a divinyl sulfone, and was purified in the same manner as from D-galactose gel, but the Stx2e sample contained some contamination. These results indicate that Stx2e bound to D-galactose gel mainly through the divinyl sulfone group on the resin and to a lesser extent through α-D-galactose. With these methods, the yields of Stx2e and attenuated mutant Stx2e (mStx2e) from 1 L of culture were approximately 36 mg and 27.7 mg, respectively, and the binding capacity of the D-galactose gel and thiophilic adsorbent resin for Stx2e was at least 20 mg per 1 ml of resin. In addition, using chimeric toxins with prototype Stx2 which did not bind to thiophilic adsorbent resin and some types of mutant Stx2e and Stx2 which contained inserted mutations in the B subunits, we found that, at the least, asparagine (amino acid 17 of the B subunits) was associated with Stx2e binding to the divinyl sulfone group. The mStx2e that was isolated exhibited vaccine effects in ICR mice, indicating that these methods are beneficial for large-scale preparation of Stx2e toxoid, which protects swine from edema disease.