Factors controlling ion-exchange selectivity in suppressed ion chromatography

Pohl, Christopher A.; Stillian, John R.; Jackson, Paul

doi:10.1016/s0021-9673(97)00705-x

Cited by 97 publications

(41 citation statements)

References 13 publications

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“…This is more obvious with the more retained hydrophobic solutes, such as 3-methoxytyramine. Similar phenomena were also observed in the other related ion exchange processes [43].…”

supporting

confidence: 86%

Application of silica-based hyper-crosslinked sulfonate-modified reversed stationary phases for separating highly hydrophilic basic compounds

Luo

Paek

et al. 2008

Journal of Chromatography A

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The separation and determination of hydrophilic basic compounds are of great importance in many fields including clinical and biological research, pharmaceutical development and forensic analysis. However, the most widely used analytical separation technique in these disciplines, reversed-phase liquid chromatography (RPLC), usually does not provide sufficient retention for several of the important classes of highly hydrophilic basic compounds including catecholamines, many drug metabolites and many drugs of abuse. Commonly eluents having little or no organic modifier and/ or strong ion pairing agents must be used to achieve sufficient retention and separation. Use of highly aqueous eluents can lead to column failure by dewetting, resulting in poor retention, selectivity, reproducibility and slow recovery of performance. The use of a strong ion pairing agent to increase retention renders the separation incompatible with mass spectrometric detection and complicates preparative separations. This paper describes the successful applications of a novel type of silica-based, hyper-crosslinked, sulfonate-modified reversed stationary phase, denoted as − SO 3 -HC-C 8 -L, for the separation of highly hydrophilic cations and related compounds by a hydrophobically assisted cation-exchange mechanism. Compared to conventional reversed-phases, the − SO 3 -HC-C 8 -L phase showed significantly improved retention and separation selectivity. Concurrently, due to the presence of both cation-exchange and reversed-phase retention mechanisms and the high acid stability of hypercrosslinked phases, the separation can be optimized by changing the type or concentration of ionic additive or organic modifier, and by varying the column temperature. In addition, gradients generated by programming the concentration of either the ionic additive or the organic modifier can be applied to reduce the analysis time without compromising resolution. Furthermore, remarkably different chromatographic selectivities, especially toward cationic solutes, were observed upon comparison of the − SO 3 -HC-C 8 -L phase with conventional reversed-phases. We believe that the combination of these two types of stationary phases will be very useful in two-dimensional liquid chromatography.

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“…This is more obvious with the more retained hydrophobic solutes, such as 3-methoxytyramine. Similar phenomena were also observed in the other related ion exchange processes [43].…”

supporting

confidence: 86%

Application of silica-based hyper-crosslinked sulfonate-modified reversed stationary phases for separating highly hydrophilic basic compounds

Luo

Paek

et al. 2008

Journal of Chromatography A

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“…These features have led to widespread usage of agglomerated ion-exchangers and many applications have been published in recent years. [17][18][19][20][21][22][23][24][25][26] There is a further interesting aspect of this type of resin. The occurrence of oppositely charged groups at the core of particle 566 ANALYTICAL SCIENCES JUNE 2000, VOL.…”

Section: ·1 Agglomerated Ion-exchangersmentioning

confidence: 99%

Zwitterionic Ion-Exchangers in Liquid Chromatography

Nesterenko

Haddad

2000

ANAL. SCI.

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The idea of combining both anion-and cation-exchange groups in a single particle of ion-exchange resin for the purpose of improvement of ion-exchange selectivity appeared shortly after the invention of polymeric ion-exchange resins. Stach 1 synthesised a zwitterionic ion-exchange resin containing both sulfonic acid and quaternary ammonium functional groups in 1951. This material was obtained by copolymerization of styrene and vinylchloride, followed by the introduction of quaternary ammonium functional groups by reaction of chloro-groups with trimethylamine, and then sulfonation with sulfuric acid to give sulfonic acid groups. However this first zwitterionic exchange resin was not fully characterized and its physico-chemical properties and performance were not evaluated. Originally, phenolformaldehyde polycondensation type resins were very popular and the occurrence of anion-exchange functional groups and residual phenol groups provided some zwitterionic properties for this material in alkaline media where the phenol group was dissociated. These resins had a monotonic distribution of functional groups over the entire volume of the resin. Since 1951 the approaches to the synthesis and design of zwitterionic ion-exchangers were directed towards localization of the oppositely charged groups in a bonded layer on the surface of the particle or on attached molecules.Zwitterionic ion-exchangers are considered to include only those materials that contain the charged groups in a single particle, rather than mixed-bed ion-exchangers where a mixture of cation-and anion-exchangers is used. However, agglomerated ion-exchangers containing a layer of electrostatically retained microbeads around a core particle of opposite charge fall under the scope of this review. In some sources of literature the terms amphoteric and bipolar ion-exchangers have been also used. 2The distribution of the oppositely charged groups can vary considerably and the following types of zwitterionic ionexchangers can be identified: (i) Polyampholyte resins having a continuous distribution of oppositely charged groups in the whole volume of the ionexchange particle. (ii) Pellicular resins containing a layer of opposite charge on a charged core particle, with this layer comprising microparticles, latex microbeads, a polymer film, or a simple treated outer surface of the core (e.g. sulfonated), for the purpose of adding functional groups of opposite charge sign to the functional groups on the core. Zwitterionic ion-exchangers represent a new direction in the development of stationary phases for different modes of high-performance liquid chromatography. The combination of positively and negatively charged sites in a single particle, or within the functional groups of a single molecule attached to the surface of an adsorbent, provides unique opportunities to vary the selectivity of separation. The classification of zwitterionic ion-exchangers based on their structure, distribution of oppositely charged groups, and their applications is considered.

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“…The number of enzymesupport interactions necessary to fix the enzyme to the support may be controlled by controlling the medium (Pohl et al, 1997). For example using an ion exchanger, the higher the ionic strength, the higher the number of enzyme-support interactions required to fix the enzyme to the support.…”

Section: Selective Immobilization Of Large Multimeric Proteins Inmentioning

confidence: 99%

“…As selective adsorbents, cationic groups that require a multipoint ionic exchange to fix the protein on the support have been utilized (Kumar et al, 2000, Pohl et al, 1997, Porath, 1992.…”

Section: One-step Immobilization-purification Of Poly-lys Tagged Protmentioning

confidence: 99%

Strategies for the one-step immobilization–purification of enzymes as industrial biocatalysts

Barbosa

Ortíz

Berenguer-Murcia

et al. 2015

Biotechnology Advances

613

318

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Enzyme immobilization and purification are two steps that are usually required in the development of any industrial biocatalyst. In this review, we detail the efforts performed to couple the purification and the immobilization of industrial enzymes in a single step. The use of antibodies (versus the target enzyme or versus some domains), the development of specific domains with affinity for some specific supports or just to increase the affinity for standard ones (ionic exchangers, silicates) will be revised. We will show how the control of the immobilization conditions may convert some unspecific supports in largely specific ones. The development of tailormade heterofunctional supports as a tool to immobilize-stabilize-purify some proteins will be discussed in deep, using low concentration of adsorbents groups and a dense layer of groups able to give an intense multipoint covalent attachment. The final coupling of mutagenesis and tailor made supports will be a the last part of the review.

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Factors controlling ion-exchange selectivity in suppressed ion chromatography

Cited by 97 publications

References 13 publications

Application of silica-based hyper-crosslinked sulfonate-modified reversed stationary phases for separating highly hydrophilic basic compounds

Application of silica-based hyper-crosslinked sulfonate-modified reversed stationary phases for separating highly hydrophilic basic compounds

Zwitterionic Ion-Exchangers in Liquid Chromatography

Strategies for the one-step immobilization–purification of enzymes as industrial biocatalysts

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