Novel polymer-based anion-exchangers with covalently-bonded functional layers of quaternized polyethyleneimine for ion chromatography

Polyelectrolyte-grafted anion exchangers with hydrophilic intermediate layers for ion chromatography

The hydrophobicity of polymer-based anion exchangers is a persistent problem in suppressed anionic chromatography (SAC) due to its adverse effect on chromatographic performance. Herein we describe polyelectrolyte-grafted anion exchangers with modified hydrophilic intermediate layers. The anion exchangers were functionalized by successively grafting a linear cationic condensation polymer (LCCP), a preprepared polyelectrolyte. The carboxylic/hydroxylic intermediate layers formed during thiol-radical-mediated polymerization exert distinct effects on the phase capacity and hydrophobicity. The separation of typical inorganic anions, polarizable anions, and organic acids shows that the anion exchangers display good performance in SAC mode.

A strong anion exchanger of poly(glycidyl methacrylate-divinylbenzene) substrate functionalized with cationic quaternary ammonium monomer

A strong anion exchanger applied for ion chromatography is described by grafting methacrylamido propyl trimethyl ammonium chloride onto hydrolyzed poly(glycidyl methacrylate-divinylbenzene) substrate. The anion exchanger has been in detail characterized and the final capacity of the anion exchanger can be readily manipulated by different monomer amounts. It exhibited obvious temperature-sensitive property and large tolerance to the samples with high ionic strength. The obtained anion exchanger demonstrated effective separation ability towards the common seven inorganic anions within 12 min and high separation efficiency, e.g. 58,000 /m of theoretical plate count for chloride. This article is protected by copyright. All rights reserved.

Preparation of an anion stationary phase modified by quaternary ammoniated allyl glycidyl ether

制备了一种季铵化烯丙基缩水甘油醚(allyl glycidyl ether, AGE)改性聚合物基质的阴离子固定相应用于离子色谱系统。它是利用AGE与水解的聚甲基丙烯酸缩水甘油酯-二乙烯基苯(poly(glycidylmethacrylate-divinylbenzene, GMA-DVB)微球表面残留双键通过表面自由基共聚,再通过N,N-二甲基乙醇胺(一种叔胺)进行开环反应制备得到的。通过考察有机叔胺类型、微球水解、单体和引发剂用量、反应温度和时间对7种阴离子分离性能的影响,优化了制备条件。采用扫描电镜、元素分析对所得阴离子固定相进行了表征。结果表明,采用预先水解的GMA-DVB微球(水解过程中微球表面丰富的环氧基团转化为羟基)相对于直接采用GMA-DVB微球有助于降低固定相的交换容量和微球自身的非离子吸附作用;通过淋洗液浓度和目标离子保留因子的拟合结果证实了该固定相保留机理为典型的离子交换作用。使用碳酸根淋洗液,在优化的色谱条件下,该固定相可在13 min内实现常见7种无机阴离子的基线分离,并表现出较高的柱效(Cl^-理论塔板数为49000块/m)。该色谱柱实用性通过分析自来水实际样品进行了验证。

Dendrimer-functionalized hydrothermal nanosized carbonaceous spheres as superior anion exchangers for ion chromatographic separation

Polyamidamine (PAMAM) dendrimer-functionalized hydrothermal nanosized carbonaceous spheres (HNCSs) were prepared and utilized as latexes for agglomerated anion exchange chromatography (AEC) stationary phase. The high-concentration and scalable production of monodisperse HNCSs (73-98 nm) was accomplished via the polyquaternium-7-assisted hydrothermal carbonization of fructose. The novel PAMAM-based quaternizations of HNCSs were designed by the amidation with PAMAM and epoxy-amine addition reaction with glycidol in aqueous solution. The mild functionalization condition leads to well-kept morphology of HNCSs, which forms one even latex layer on the sulfonated surface of polystyrene-divinylbenzene microbeads for the construction of AEC packing. Under isocratic elution, seven common inorganic anions and five organic acids were baseline separated in 9 min on prepared packing with efficiencies of 54,000-79,800 plates m^-1 and asymmetry factor (As) of 1.02-1.12. The obtained separation efficiency, peak symmetry, and analysis time were superior to reported or typical commercial counterparts. The quick separation of polarizable anions in 7 min and carbohydrates in 5 min could also be carried out with symmetrical peaks (As: 1.00-1.18) and high efficiencies (49,700-62,100 N/m). Favorable stability and reproducibility were proved by continuous flushing and injection. The constructed packings were further applied to the determination of thiosulfate and sulfate in water reducer, galacturonic acid in Angelica polysaccharide hydrolysate, and fluoride samples in 4 min.

A review of the design of packing materials for ion chromatography

The development of ion chromatography has made remarkable progress in the past few decades, and it is now widely used for the analysis of common ions and organic compounds. Ion chromatography has many advantages, such as fast, high sensitivity, good selectivity and support for simultaneous analysis of multiple ionic compounds. In order to meet the high requirements of material analysis, new packing materials for ion chromatography with higher sensitivity and selectivity have been developed. In this paper, a lot of knowledge of ion chromatography is reviewed, and the development of ion chromatographic packings in recent years, especially in the last five years, is summarized.

Synthesis, Characterization, and Properties of Sulfonated Chitosan for Protein Adsorption

Chitosan sulfate was prepared and characterized as a new chromatography media for protein separation. The degree of sulfonation of chitosan could be well controlled and impacted under conditions in the synthesis process. The prepared chitosan sulfate shows improved binding capacity with proteins. Sulfonated chitosan shows improved ion-exchange adsorption properties with proteins, which could have good potential in protein purification.

Preparation and application of PGMA-DVB microspheres via surface-modification with quaternary and phenylboronic acid moiety

Porous cross-linked poly (glycidyl methacrylate-divinylbenzene) (PGMA-DVB) particles (7.42 ± 0.24 μm in diameter) were prepared by an improved two-step seed swelling polymerization method. The PGMA-DVB particles were further modified with poly (allylamine hydrochloride) (PAH) and 4-(bromomethyl) phenylboronic acid (BPA), which were used as high performance liquid chromatography (HPLC) filler for nucleotides separation. The liquid chromatographic column packing materials successfully achieved complete separation of nucleotides mixture or deoxynucleotides mixture based on non-polar adsorption, hydrogen bonding interaction and electrostatic adsorption. Reckoning on the chemical structure of BPA, nucleotides and deoxynucleotides with same base group were also separated. The column packing materials were durable after over 100 time running or 7 days. It presents a kind of new notion for the separation of nucleotides by HPLC.

Quantification of volatile fatty acids from cattle manure via non-catalytic esterification for odour indication

This report proposes a new approach to evaluate the odour nuisance of cattle manure samples from three different cattle breeds (i.e., native cattle, beef cattle, and milk cow) by means of quantification and speciation of volatile fatty acids (VFAs). To this end, non-catalytic esterification thermally induced in the presence of a porous material (silica) was undertaken, and the optimal operational parameters such as the derivatizing temperature (330°C) for the maximum yield (≥99±0.4%) of volatile fatty acid methyl esters (VFAMEs) were established. Among the VFA species in cattle manure based on quantification of VFAs, the major species were acetic, butyric and valeric acid. Considering the odour threshold of each VFA, our experimental results suggested that the major contributors to odour nuisance were C_4-5 VFA species (i.e., butyric and valeric acid). Hydrothermal treatment was performed at 150°C for 0-40min to correlate the formation of VFAs with different types of cattle feed formulations. Our experimental data demonstrated that the formation of total VFAs is linearly proportional to the hydrothermal treatment duration and the total content of VFAs in native cattle, beef cattle, and milk cow manure samples reached up to ~1000, ~3200, and ~2800ppm, respectively. Thus, this study demonstrated that the degree of VFA formation is highly dependent on cattle feed formulations, which rely significantly on the protein content. Furthermore, the hydrothermal treatment provides a favourable condition for generating more VFAs. In this context, producing cattle manure into refused derived fuel (RDF) via a hydrothermal treatment is not a viable option to control odour.