Multifunctional Zwitterion-Exchange Stationary Phase for HPLC

Chou, Tsong-Yung; Yang, Mei‐Hui

doi:10.1080/10826079608015121

Cited by 5 publications

(2 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[51][52][53] In the first step, silica gel was treated with N-phenylaminomethyl(triethoxy)-silane or with N-(2-aminoethyl)-3-aminopropyltriethoxysilane to produce a weak anionexchanger containing active secondary or primary amino groups, respectively. The prepared substrates were then reacted with chlorosulfonic acid or with the p-sulfanilic derivative of cyanuric chloride resulting in partial introduction of sulfonate groups (see Fig.…”

Section: ·2 Multifunctional Zwitterionic Exchangersmentioning

confidence: 99%

Zwitterionic Ion-Exchangers in Liquid Chromatography

Nesterenko

Haddad

2000

ANAL. SCI.

View full text Add to dashboard Cite

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.

show abstract

Section: ·2 Multifunctional Zwitterionic Exchangersmentioning

confidence: 99%

Zwitterionic Ion-Exchangers in Liquid Chromatography

Nesterenko

Haddad

2000

ANAL. SCI.

View full text Add to dashboard Cite

show abstract

“…However, simultaneous separation of halide anions and divalent cations has not been shown . Meanwhile, several other zwitterionic separation media capable of separating organic or inorganic substances have also been described in the literature, , all being based on the matrix of silica.…”

mentioning

confidence: 99%

Covalently Bonded Polymeric Zwitterionic Stationary Phase for Simultaneous Separation of Inorganic Cations and Anions

1998

View full text Add to dashboard Cite

Gas and Liquid Chromatography, Column Selection for, in Drug Analysis

Duff

2000

Encyclopedia of Analytical Chemistry

View full text Add to dashboard Cite

Within the realm of pharmaceutical drug analyses, two techniques currently dominate the field. High‐performance liquid chromatography (HPLC) is at the forefront, followed somewhat distantly by gas chromatography (GC). HPLC is more prevalent than GC owing mainly to the heat‐labile nature of the majority of drug substances. Still GC continues to play a very active role. In comparison to HPLC and GC, combined, the frequency of use of other techniques is quite small. Perhaps the major reason for this is that chromatography not only involves qualitative and quantitative detection of targeted species, but also provides a medium for isolating these analytes from potential interfering impurities prior to measurement. The proficiency of this combination is unparalleled by any other blending of means to clean up a sample and detect the target compound. These more prominent techniques are often complementary, although each has its own strengths and limitations. General guidelines are given to assist the chromatographer to elect HPLC and/or GC for a particular separation. Considerations for choosing hardware type and sizes, solid support and bonded phase are presented. Particular emphasis is placed on the latest, which is of primary importance for obtaining rugged methods. The reader is directed towards optimum phase selection based on the compound of interest's functional group type, or by its drug activity classification (e.g. barbiturate, cardiovascular, etc.). Assistance in developing new methods frequently arises when starting with an existing published method for a compound with similar structure. This article provides 514 references for more in‐depth separation information. In addition, background knowledge on bonded‐phase chemistry, chromatographic modes of separation, approaches to chromatographic chiral drug discrimination and processes for developing rugged methods is contributed.

show abstract

Multifunctional Zwitterion-Exchange Stationary Phase for HPLC

Cited by 5 publications

References 11 publications

Zwitterionic Ion-Exchangers in Liquid Chromatography

Zwitterionic Ion-Exchangers in Liquid Chromatography

Covalently Bonded Polymeric Zwitterionic Stationary Phase for Simultaneous Separation of Inorganic Cations and Anions

Gas and Liquid Chromatography, Column Selection for, in Drug Analysis

Contact Info

Product

Resources

About