Anion Exchange Resin Column Research Articles

Demonstration scale chemical–physical treatment and agricultural reuse of highly saline textile wastewater

AbstractThis study aimed to develop an energy‐efficient process for treating highly saline textile wastewater (TWW) in a 10 m3/day pilot plant and evaluate forage sorghum irrigation with treated wastewater in terms of crop production and soil and irrigation device performance. The TWW treatment pilot plant, consisting of a coagulation/flocculation unit followed by a sand filter and an anion exchange resin column, produced treated effluent that complied with the permissible limits specified in the ISO 16075‐2:2020 standard for Category C irrigation water. The corresponding average energy consumption was 1.77 kWh/m3. Reusing treated TWW for forage sorghum irrigation over a 13‐week cycle yielded crop performances comparable with freshwater irrigation, with no negative impact on the irrigation system. Although soil profiles were similar between treated TWW and freshwater irrigation, both soils featured an increase in electrical conductivity, which may reversibly or irreversibly affect soil quality and damage salt‐sensitive crops. These findings demonstrate the effective treatment and reuse of saline TWW for irrigating salt‐tolerant crops, offering significant implications for industrial wastewater management and cropping patterns in arid and semi‐arid regions.

Determination of ultra-trace Te species in open ocean waters based on Mg(OH)2 coprecipitation, anion exchange resin column separation and inductively coupled plasma sector-field mass spectrometry using a 125Te-enriched isotope spike

We present a method for the determination of ultra-trace Te species (Te(IV) and Te(VI)) in open ocean waters. The proposed method is based on Mg(OH)2 coprecipitation, anion exchange resin column separation and inductively coupled plasma sector-field mass spectrometry (ICPSFMS) using a 125Te-enriched isotope spike. The largest advantage of the method is that the use of the spike allows accurate and precise determination when it combines with either isotope dilution or recovery correction. Tellurium-IV and VI are preconcentrated in a Mg(OH)2 precipitate and separated mutually by an anion exchange resin column. Te(IV) is retained to the column, while Te(VI) passing through the column is recovered by a subsequent column procedure after reduction of Te(VI) to Te(IV). Te(IV) is successfully eluted with a small amount of 0.01 M HCl. The additional merit of using this eluent is elimination of components that result in a memory effect during the measurement of Te(IV). Possible mass spectral interference on Te(IV) can be excluded by adjusting the mass window, and the Te(IV) concentrations determined by this approach agree well with those independently obtained by an oxidation procedure which removes the interference. The accuracy of the proposed method is verified with homemade standard seawater for which the measured concentrations agree well with results calculated from the value of the standard solution. Procedural blanks for Te(IV) and Te(VI) are 1.5 ± 0.9 pg kg−1 (n = 11) and 1.3 ± 0.9 pg kg−1 (n = 11) with corresponding overall detection limits of 3.0 pg kg−1 and 2.8 pg kg−1, respectively. Using the method, we have clarified vertical profiles of Te(IV) and Te(VI) in the subarctic western North Pacific for the first time.

Pilot-scale removal of PFAS from chromium-plating wastewater by anion exchange resin and activated carbon: Adsorption difference between PFOS and 6:2 fluorotelomer sulfonate

Chromium-plating wastewater is an important source of per- and polyfluoroalkyl substances (PFAS) contamination. Currently, adsorption is considered to be one of the main technologies for the removal of PFAS from wastewater. However, no pilot-scale studies have been conducted to investigate its application in chromium-plating wastewater and the adsorption characteristics of 6:2 fluorotelomer sulfonate (6:2 FTS), the alternative to perfluorooctane sulfonate (PFOS). In this study, we evaluated the removal of PFAS from chromium-plating wastewater by granular activated carbon (GAC) and anion exchange resin (AER) at a pilot-scale. The breakthrough curves of PFOS and 6:2 FTS were similar in GAC columns, but significantly different in AER columns, with PFOS and 6:2 FTS reaching 10% breakthrough at about 45,000 BV and 4,000 BV, respectively. The replacement of 6:2 FTS by PFOS and other coexisting organic substances resulted in the concentrations of 6:2 FTS in the AER effluent reaching up to 3.8 times the influent concentrations. Density functional theory (DFT) calculations showed that the adsorption energy of PFOS on the quaternary amine group of AER was more negative than that of 6:2 FTS, and the weak affinity of AER for 6:2 FTS was closely related to the solvent effect. According to the cost analysis, if 6:2 FTS becomes the target PFAS, AER adsorption will no longer have a cost advantage over GAC adsorption. This study can provide technical support for the adsorptive removal of PFAS from electroplating wastewater and guide the development of efficient adsorbents for PFAS alternatives.

Effect of sturgeon protein in promoting the adhesion of Lactobacillus plantarum and Lactobacillus rhamnosus

Dietary protein could serve as primary nitrogen source for intestinal flora to enhance the intestinal environment by influencing probiotic adhesion. Our work aims to demonstrate a framework for probiotic activity guided isolation of potential effective fractions from the sturgeon protein. We confirmed the isolated fractions of sturgeon protein as having probiotic adhesion activity against Lactobacillus plantarum 45 (LP45) and Lactobacillus rhamnosus GG (LGG). Three protein fractions (0%, 40%, and 60% NaCl elution fractions) were obtained through anion exchange resin column. The molecular weights of the three fractions were identified by polyacrylamide gel electrophoresis in the ranges of 20.1–66.4 kDa (Fr1), 14.3–44.3 kDa (Fr2) and 14.3–97.2 kDa (Fr3), respectively. A detailed study was performed using an in vitro adhesion model to obtain the bioactive protein. In this model, probiotics were incubated on isolated intestinal segments of mice, and the adhesion effect of probiotics was evaluated through polysaccharide analysis, biofilm quantification, viable count measurement and electron microscopy. Notably, Fr2 was identified as the most effective fractions, significantly increasing the intestinal adhesion rates of LP45 and LGG by 144.8% and 53.7%, respectively. Ultimately, the primary structure of the protein 14.3 kDa in Fr2 was identified by mass spectrometry. Partial peptide amino acid sequences of the protein were confirmed to be W-W-Y-C-F (m/z = 804), K-N-H-D-I/L-Q-A-D-D-I/L-T-C (m/z = 1510) and Q-M-V-H-K-I/L-E-D-E-E-I/L-C-T-S-A-D-K-D (m/z = 2300). In conclusion, we found evidence that purified fractions of sturgeon protein facilitates the adhesion of intestinal probiotics and can be used as an active protein beneficial for intestinal health.

Removal of Silicic Acid from Feed Water Using a Tiron Combined Anion Exchange Resin Column

Thorough removal of silicic acid from treated water, as a water pretreatment procedure, is essential for the prevention of silica deposits on anion exchange resins and reverse osmosis membranes. In this study, thorough removal of silicic acid was achieved using a Tiron (1,2-dihydroxy-3,5-benzendisulfonate) combined resin. In the column experiment, it was confirmed that silicic acid could be removed below the detection limit of the molybdenum-blue methods. Tiron, which can form a stable 1:3 Si-Tiron complex in aqueous solutions, merges anion exchange resins (Tiron resin) and exhibits a strong silicic acid removal ability over a wide pH range (pH 2–10). In the regeneration process, silicic acid could be easily removed from the Tiron resin through acid treatment (pH 2, HCl), and a mild alkaline treatment (pH 8, NaOH solution) was used to restore the silicic acid removal ability. Following the acid and alkaline treatments, the removal ability of the regenerated Tiron resin was maintained, suggesting that the resin could be reused in water treatment systems. Excess inorganic anion species did not affect silicic acid removal.

A single-stage anion exchange separation method for Cd isotopic analysis in geological and environmental samples by MC-ICP-MS

A single-stage column separation method based on an anion exchange resin column is developed to purify Cd from geological and environmental materials for high-precision determination of Cd isotopes by double spike MC-ICP-MS.

Effects of counterion type on selective arsenic removal process combining standard anion exchange resin with electrocoagulation for polluted groundwater

This study achieved the highly selective removal of trace arsenic (As) from groundwater (110 μg L−1 As) by the standard anion exchange resin (AER) column process during long-term exhaustion–regeneration cyclic operation by optimizing the sulfate equivalent fraction (0.97 or 0.875) in sulfate-chloride or sulfate-bicarbonate binary brine (chloride or bicarbonate as counterion). No significant (<5%) or low (maximum: 25%) sulfate removal from the feedwater were stably observed during the 20 or 21 exhaustion–regeneration cycles without brine treatment or replacement, when <10 μg L−1 As was consistently observed in the product water. Furthermore, this study demonstrated the selective As removal from As-rich sulfate-chloride or sulfate-bicarbonate spent brine by aluminum (Al)- or iron (Fe)-based chemical coagulation or electrocoagulation process. Fe-based electrocoagulation (9-cm interelectrode distance, 0.50 mA cm−2, 15 min) and sulfate-chloride binary brine are finally recommended after metal dosage, sludge production and residual metal concentration among them were compared. No electrocoagulation took place in the sulfate-bicarbonate spent brine even at a current density of 3 mA cm−2 because of high bicarbonate concentration that formed passivation film on the anode surface. Finally, a combined process including a standard AER column and spent brine electrocoagulation was developed to achieve the stability and high As-selectivity of 114 exhaustion–regeneration cycles.

Antioxidant Activity of Lignocellulose Pyrolysis by-Products after Levoglucosan Separation

Fast pyrolysis of pre-treated lignocellulose gives a high yield of levoglucosan and other anhydrosugars, which are considered as the main product. However, the chemical composition of the liquid pyrolysis products is a complex mixture of hundreds of individual compounds. To implement the biorefinery principles, it is important to find applications for the side-streams which arise during levoglucosan production. First, we separated the anhydrosugars by eluting the pyrolysis product water solution through an anion exchange resin column. The anhydrosugars were eluted, but the aromatic by-products were adsorbed on the resin. The by-products were desorbed from the resin with a mixture of methanol/water/acetic acid, and the chemical composition of the obtained by-products was analyzed by UHPLC-UV, and the Folin-Ciocalteu method. Alternatively, the pyrolysis products were separated by crystallization, which yielded levoglucosan with &gt;90% purity, and a mother liquor enriched with aromatic chemical compounds. The antioxidant activity in all samples was evaluated by the DPPH method with corrections to compensate for the color of the by-product samples, which interfered with the UV/VIS spectrophotometry readings.

Comparative investigation of PFAS adsorption onto activated carbon and anion exchange resins during long-term operation of a pilot treatment plant

Widespread contamination of groundwater with per- and polyfluoroalkyl substances (PFAS) has required drinking water producers to quickly adopt practical and efficacious treatments to limit human exposure and deleterious health outcomes. This pilot-scale study comparatively investigated PFAS adsorption behaviors in granular activated carbon (GAC) and two strong-base gel anion exchange resin (AER) columns operated in parallel over a 441-day period to treat contaminated groundwater dominated by short-chain perfluorocarboxylic acids (PFCA). Highly-resolved breakthrough profiles of homologous series of 2–8 CF2 PFCA and perfluorosulfonic acids (PFSA), including ultrashort-chain compounds and branched isomers, were measured to elucidate adsorption trends. Sample ports at intermediate bed depths could predict 50% breakthrough of compounds on an accelerated basis, but lower empty bed contact times led to conservative estimates of initial breakthrough. Homologous PFAS series displayed linear (GAC) and log-linear (AER) relationships between chain-length and breakthrough, independent of initial concentration. AERs generally outperformed GAC on a normalized bed volume basis, and this advantage widened with increasing PFAS chain-length. As designed, all treatments would have short full-scale service times (≤142 days for GAC; ≤61 days for AERs) before initial breakthrough of short-chain (2–4 CF2) PFCA. However, AER displayed far longer breakthrough times for PFSA compared to GAC (>3× treatment time), and breakthrough was not observed for PFSA with >4 CF2 in AERs. GAC had a finite molar adsorption capacity for total PFAS, leading to a stoichiometric replacement of short-chain PFCA by PFSA and longer-chain PFCA over time. AERs quickly reached a finite adsorption capacity for PFCA, but they showed substantially greater selectivity for PFSA whose capacity was not reached within the duration of the pilot. Breakthrough characteristics of keto- and unsaturated-PFSA, identified in the groundwater by suspect screening, were also evaluated in absence of reference standards. Modified PFAS structures (branched, keto-, unsaturated-) broke through faster than linear and unmodified perfluorinated structures with equal degrees of fluorination, and the effects were more pronounced in GAC compared to AERs. The results highlight that the design of robust PFAS treatment systems should consider facets beyond current PFAS targets including operational complexities and impacts of unregulated and unmonitored co-contaminants.

Applications of a dual-column technique in actinide separations

Selective separation of an individual actinide of interest from other actinides and accompanying lanthanides is a challenging task in radiochemistry and radioanalytical chemistry. This paper illustrates a dual column technique (i.e., stacked columns of two appropriate resins) to separate an individual actinide of interest, where the selection of two resins and a common effluent running through the stacked columns are key parameters in design of an appropriate dual column. This paper describes the dual column design and practice with two examples, one for a heavy actinide 249Bk and the other for a light actinide 230U. In the former case, stacked columns of anion exchange (AX) resin and LN resin replaced the traditional CX-AHIB method used at Oak Ridge National Laboratory for 60 years. In the latter case, an elution process with an AX column followed with a stacked column of AX resin and a DGA resin was applied, instead of traditional methods, e.g., PUREX or U-TEVA methods. Application results of the dual column method to the two example actinides are displayed, while the considerations in method design and the required conditions are discussed.

Preparation of a carrier free 124Sb tracer produced in the Sn (p, n) reaction

Abstract A carrier-free 124Sb tracer was prepared for determining radioactive 125Sb in highly contaminated and radioactive soil like one taken near the Fukushima Daiichi Nuclear Power Plant. The excitation function for the 124Sb production was measured and compared to previous works to identify the optimum proton energy for the 124Sn (p, n) reaction by a stack method. The maximum production of 124Sb in the reaction was found at an incident proton beam energy of 8–9 MeV. Except for 124Sb, the reaction produced short-lived by-products and practically no 125Sb. Antimony was isolated from tin matrix by dissolving the irradiated target and extracting to isoamyl acetate. Then the carrier-free 124Sb tracer solution was purified by passing it through an anion exchange resin column. The radioactivity of 124Sb was recovered to more than 50% of the production, and provided successfully as a tracer solution free from tin due to the examined chemical procedure.

Boron Removal from Aqueous Solutions by Strong Base Anion-exchange Resin Batch and Column Experiments

Borate ion exchange capacity of Purolite NRW600 strong base anion resin in hydroxide form and mixed bed NRW600+NRW100 ion exchange was investigated with static experiments. Anion exchange resin was saturated with 0.1–45 g/dm3 concentration boric acid solution in a static mixer at 20, 30, 40 and 50 °C at 150 rpm for 24 hours. Remaining borate content of saturation solutions was deter-mined with ion chromatography and ICP-OES. The amount of fixed borate as borate anions increased with the saturation borate concentration as well as in case of simple anion exchange as in case of mixed bed.Column sorption-elution study was carried out by using strong base anion exchange resins (Purolite NRW600 and Amberlite IRN78). Resins in hydroxide and in chloride forms were saturated in column with 5–40 g/dm3 boric acid solution in excess. The resin was then eluted with 200 cm3 salt free water with 5 cm3/min at 25 °C and then eluted by 1 mol/dm3 sodium-sulfate solution with 5 cm3/min. The effluent was collected and analyzed for borate content by titrimetric method. In chloride form the resin adsorbed and released much less borate. Effective borate and polyborate sorption needs hydroxide ions in resin phase.

Simplified Method for the In Situ Collection and Laboratory Analysis of Cosmogenic Tracers (Sulfur-35 and Sodium-22) to Determine Residence Time Distributions and Water Ages

The use of cosmogenically produced sulfur-35 (T1/2 = 87 days) and sodium-22 (T1/2 = 2.6 years) as intrinsic tracers can provide valuable information on catchment hydrology, flow paths, and subsurface storage. A new and straightforward method was created to determine the activities of both 35S and 22Na in various water sources by pumping large volumes (up to 1000 L) of water through cation- and anion-exchange resin columns in the field to collect sodium and sulfate ions and simple chemistry in the lab. Samples are counted for 35S using liquid scintillation counting (LSC) and for 22Na via γ spectroscopy. Our novel in situ method provides faster sample throughput as well as better counting statistics and lower detection limits. Both methods were successfully applied at the Southern Sierra Critical Zone Observatory.

Catecholic alkaloid sulfonates and aromatic nitro compounds from Portulaca oleracea and screening of their anti-inflammatory and anti-microbial activities

Acidic compounds were enriched from a water decoction of Portulaca oleracea using 717 anion exchange resin column chromatography. A total of 22 compounds including 9 catecholamine derivatives, of which six were rare sulfonic acid derivatives, and 9 nitro derivatives, were further isolated through various column chromatographic methods, and their structures were elucidated by interpreting their spectroscopic data and ECD calculations. Among them, 16 compounds were isolated from P. oleracea for the first time, 8 of which were undescribed compounds and four compounds were natural products. Pharmacological screening indicated that cis-3-(3-nitro-4-hydroxyphenyl)-methyl acrylate exhibited anti-inflammatory activity, measured as inhibition of nitric oxide production in LPS-stimulated RAW264.7 macrophage cells, with an EC50 value of 18.0μM, The compounds showed only weak anti-microbial activity with (2R)-(+)-2-chloro-3-(3-nitro-4-hydroxyphenyl)-propionic acid methyl ester inhibiting Candida albicans with a MIC of 256μg/mL, and 3-methoxy-4,5-dinitrophenol inhibiting Shigella sonnei with a MIC of 512μg/mL.

Removal of organic matter from wastewater reverse osmosis concentrate using granular activated carbon and anion exchange resin adsorbent columns in sequence

Reverse osmosis concentrate (ROC) generated as a waste stream during reverse osmosis treatment of reclaimed wastewater, presents significant disposal challenges. This is because it causes environmental pollution when it is disposed to lands and natural water bodies. A long-term dynamic adsorption experiment was conducted by passing ROC from a wastewater reclamation plant, firstly through a granular activated carbon (GAC) column, and subsequently through an anion exchange resin (Purolite) column, for the removal of two major ROC pollutants, namely dissolved organic carbon (DOC) and microorganic pollutants (MOP). GAC removed most of the smaller-sized low molecular weight neutrals and building block fractions as well as the hydrophobic fraction of DOC with much less removal by the subsequent Purolite column. In contrast, the humics fraction was less well removed by the GAC column; however, Purolite column removed all that was remaining of this fraction. This study demonstrated that combining adsorbents having different affinities towards a variety of DOC fractions constitute an effective method of taking advantage of their different properties and achieving larger DOC removals. Almost 100% of all 17 MOPs were removed by the GAC column, even after 2880 bed volumes of continuous use. This contrasted with the DOC fractions’ removal which was much lower.

Method Development and Validation of Ion Chromatography Method for Determination of Free Sulfate in Fondaparinux Sodium Pre-Filled Syringe

A simple ion chromatography method was developed for the quantitative determination of free sulfate in fondaparinux sodium pre-filled syringe for injection. Chromatographic separation was achieved on an anion-exchange resin column made of super macro porous polyvinyl benzyl ammonium polymer cross-linked with divinyl benzene (250 × 4.0 mm) with a mobile phase consisting of 60 mM carbonate buffer solution. Conductivity detector was employed with a flow rate of 0.7 mL min-1, injection volume of 100 μL and column temperature of 30 ºC. Retention time of sulfate (SO4 2−) was eluted at about 10.4 min. The developed method was validated in according to ICH Q2(R1) guideline and was found to be specific, precise, accurate, linear and robust. The precision was evaluated with six individual spiked samples of sulfate on Fondaparinux sodium for injection. The proposed method is linear (r2 &gt; 0.9991) and accurate, mean recoveries were 99.2-117.8 % at 3 different levels (50-150%). The robustness was performed by changing the flow rate of mobile phase (0.7 ± 0.1mL min-1) and column temperature (30 ± 2 ºC). The proposed method is capable to determine free sulphate in fondaparinux sodium for injection in presence of excipients used in pharmaceutical formulation and also in its active pharmaceutical ingredient.

Simultaneous Analysis of Iodine and Bromine Species in Infant Formula using HPLC-ICP-MS.

Background: A fast and sensitive method for the simultaneous analysis of iodine and bromine species in infant formula was developed using HPLC-inductively coupled plasma-MS (HPLC-ICP-MS). Method: To determine the four halogen species [iodide (I-), iodate <inline-formula><mml:math display="inline"><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">IO</mml:mi></mml:mrow><mml:mn>3</mml:mn><mml:mo>-</mml:mo></mml:msubsup></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:math></inline-formula>, bromide (Br-), and bromate <inline-formula><mml:math display="inline"><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">BrO</mml:mi></mml:mrow><mml:mn>3</mml:mn><mml:mo>-</mml:mo></mml:msubsup></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:math></inline-formula>] in a milk-based Standard Reference Material and four commercially available infant formula products. Results: The four halogen species were baseline separated in less than 6.5 min using an anion exchange resin column and 5.0 mM NaH₂PO₄ / 15.0 mM Na₂SO₄ / 5.0 mM EDTA (pH 7.0) mobile phase. Following separation, the halogen species were detected by measuring m/z 79 for Br and m/z 127 for I using a triple quadrupole-ICP-MS. The instrument was operated in single quadrupole mode with helium cell gas. Excellent linearity (R = 0.9999 or better) was obtained for all four species with calibration standards ranging from 0 to 100 ppb. The LOD for I-, <inline-formula><mml:math display="inline"><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">IO</mml:mi></mml:mrow><mml:mn>3</mml:mn><mml:mo>-</mml:mo></mml:msubsup></mml:math></inline-formula>, Br-, and <inline-formula><mml:math display="inline"><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">BrO</mml:mi></mml:mrow><mml:mn>3</mml:mn><mml:mo>-</mml:mo></mml:msubsup></mml:math></inline-formula> were all less than 0.67 μg/kg. To test the suitability of the method for the accurate determination of low concentrations of the four species in infant formula samples, a spike recovery test was carried out at 20 and 40 μg/kg into the diluted infant formula samples. Conclusions: Total elemental determinations of iodine and bromine were also performed using the triple quadrupole-ICP-MS without HPLC.

Inhibition of Silicic Acid Elution during the Regeneration of Strong Base Anion Exchange Resin Column

Abstract To determine why silicic acid elution is often incomplete during regeneration of strong base anion exchange resin columns, an OH− type anion exchange resin (OH− type resin) adsorbing silicic acid was prepared and the desorption (elution) behavior of silicic acid adsorbed to the resin was examined by batch and column experiments. It was first found that silicic acid adsorbed to an OH− type resin polymerizes to form polysilicic acids (Q1, Q2 and Q3 structures) even when a smaller amount of silicic acid than the ion exchange capacity was adsorbed (unsaturated adsorption). Consequently, elution of silicic acid from the OH− type resin column is most likely caused by hydrolytic decomposition of polysilicic acid. Silicic acids with Q0, Q1 and Q2 structures can be easily desorbed from the OH− type resin by immersing them in a 1% NaOH solution for 5 min. On the other hand, silicic acid with the Q3 structure is barely desorbed. In this study, incomplete elution of silicic acid from OH− type resin columns has been found to be caused by polymerization of adsorbed silicic acid and the elution behavior may depend on the polymerization mode.

Rapid determination of bongkrekic acid in Liushenqu by ultra performance liquid chromatography-tandem mass spectrometry

A method for the rapid determination of biotoxin (bongkrekic acid) in the Liushenqu was established using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with methanol by ultrasonication, then the pH was adjusted to 8 using ammonia. After filtration, the extract was purified using an Oasis Max strong anion exchange resin column. The Waters HSS T3 column (100 mm×2.1 mm, 1.8 μm) was used for the UPLC-MS/MS analysis. The mobile phase was acetonitrile-10 mmol/L ammonium formate solution (containing 0.1% (v/v) formic acid). MS analysis was performed using an electrospray ionization (ESI) source in the negative and multiple reaction monitoring (MRM) modes. Under the optimum conditions, the linear range of bongkrekic acid was 0.5-100 μg/L (correlations coefficient (R2)>0.99). The recoveries of the bongkrekic acid were 80.6%-85.3%. The intra-day and inter-day relative standard deviations (RSDs) were in the range of 4.2%-6.8% and 8.2%-13.2%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were 0.4 μg/kg and 1.2 μg/kg, respectively. The results showed that bongkrekic acid residues were detected in Liushenqu, thereby confirming the supporting role of our method for the risk monitoring of biotoxins in health foods and Chinese herbal medicines. This method is simple, easy, sensitive, and suitable for the determination of the bongkrekic acid residues in Liushenqu.

Applications of MP-1 anion exchange resin and Eichrom LN resin in berkelium-249 purification

Purification of berkelium-249 (249Bk) at Oak Ridge National Laboratory requires a multi-step process with Bk Finishing as the final step. The current multi-process takes 6–7 months, including ~ 3 months spent on Bk Finishing. Recent trials of using columns of either LN resin or MP-1 anion exchange resin adsorbing the tetravalent 249Bk4+ in 8M HNO3-0.5M NaBrO3, followed by eluting impurities (e.g. Ce4+, Cf3+) and stripping 249Bk resulted in a new dual column method of selectively separating 249Bk from other trans-curium elements and fission product impurities, which is proposed to replace the current Bk Finishing with higher Bk purification efficiency and shorter processing period. This paper displays the experimental results and describes the dual column method with relevant chemistry issues.