Polar bonded phase with the zwitterionic sulfobetaine functional group

Tramposch, Walter G.; Weber, Stephen G.

doi:10.1016/s0021-9673(01)83981-9

Cited by 8 publications

(3 citation statements)

References 7 publications

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“…Zwitterionic surfactants have seen only limited use in analytical separations. In chromatography zwitterionic surfactants have been used as a stationary phase modifier, micellar mobile phase, and polar bonded stationary phase . In CZE, sub-cmc concentrations were used in conjunction with organic solvents to separate proteins and peptides on the basis of minor differences in their hydrophobic character.…”

Section: Resultsmentioning

confidence: 99%

Suppression of Electroosmotic Flow and Prevention of Wall Adsorption in Capillary Zone Electrophoresis Using Zwitterionic Surfactants

1997

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Addition of zwitterionic surfactants such as dodecyldimethyl(3-sulfopropyl)ammonium hydroxide, hexadecyldimethyl(3-sulfopropyl)ammonium hydroxide, and coco (amidopropyl)hydroxyldimethylsulfobetaine (Rewoteric AM CAS U) to an electrophoretic buffer suppress the electroosmotic flow by 50-90%. Onset of suppression occurs at approximately the critical micelle concentration of the surfactant. CAS U effectively suppresses the electroosmotic flow over the pH range 3-12. Addition of 2 mM CAS U to the electrophoretic buffer prevents adsorption of cationic proteins lysozyme, α-chymotrypsinogen A, cytochrome c, and ribonuclease A. Migration time reproducibility for these proteins is ∼1% RSD within 1 day and 2-5% from day to day. Efficiencies in excess of 750 000 plates/m and recoveries of >80% were observed for protein injections from distilled water. Alternatively if 2 mM CAS U is added to samples, recoveries were quantitative, although efficiencies decreased to 325 000-600 000 plates/m. The natural electroosmotic flow of the capillaries is regenerated simply by rinsing with sodium hydroxide.

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Section: Resultsmentioning

confidence: 99%

Suppression of Electroosmotic Flow and Prevention of Wall Adsorption in Capillary Zone Electrophoresis Using Zwitterionic Surfactants

1997

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“…In fact, there are many reports concerning chromatographic separation with zwitterionically modified materials, although it is still one of the new liquid chromatography separation modes studied in recent years. − Hu et al established the zwitterionic functionality via dynamically adsorbing the ODS (octadecyl silica) column with a sulfobetaine-type zwitterionic surfactant by the interaction between the C 18 groups on the surface and the hydrophobic tail of the surfactant. To overcome the drawback of inferior stability due to loss of functional moieties from the dynamically attached layer on the surface of stationary phases, covalently bonded zwitterionic separation materials for liquid chromatography were prepared by direct surface reaction or surface graft polymerization. , Zwitterionic monoliths were also prepared by photoinitiated copolymerization of monomers with zwitterionic functional groups and methacrylic cross-linkers . The zwitterionic stationary phases for high performance liquid chromatography columns show the ability of simultaneous separation of inorganic anions and cations and also acidic and basic proteins in a single run .…”

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confidence: 99%

Monolithic Column with Zwitterionic Stationary Phase for Capillary Electrochromatography

Xie

Dong

et al. 2004

Anal. Chem.

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A capillary electrochromatography (CEC) monolithic column with zwitterionic stationary phases was prepared by in situ polymerization of butyl methacrylate, ethylene dimethacrylate, methacrylic acid, and 2-(dimethyl amino) ethyl methacrylate in the presence of porogens. The stationary phases have zwitterionic functional groups, that is, both tertiary amine and acrylic acid groups, so the ionization of those groups on the zwitterionic stationary phase was affected by the pH values of the mobile phase, and further affects the strength and direction of the electroosmotic flow (EOF). Separations of alkylbenzenes and polycylic aromatic hydrocarbons based on the hydrophobic mechanism were obtained. Separation of various types of polar compounds, including phenols, anilines, and peptides, on the prepared column were performed under CEC mode with anodic and cathodic EOF, and different separation selectivities of those polar analytes were observed on the monolithic capillary column by using mobile phases with different pH values.Ionizable groups on the surface of the stationary phase are necessary to generate substantial electoosmotic flow (EOF) for capillary electrochromatography (CEC). 1 Strictly speaking, most stationary phases used in CEC are ion-exchangers. Silica-based packing materials, which have been most widely used in CEC and can be regarded as weak cation exchangers, generate cathodic EOF due to the ionization of the residual silanol groups on the surface of packings. Recently, strong ion exchangers and so-called mixed-mode packing materials consisting of ionic groups such as sulfonic acids or quaternary amines and hydrocarbon chains have attracted much attention in CEC, because these packings ensure stable EOF over an extended pH range. 2 The direction of the EOF depends on the charges on the surface of the stationary phases, so stationary phases with positively charged functional groups, such as amino groups or ammonium groups, generate an EOF from cathode to anode, whereas stationary phases carrying negatively charged groups, such as sulfonic acid and carboxylic acid, generate cathodic EOF. To date, the vast majority of reports on CEC concern EOF with one direction, that is, cathodic or anodic EOF, for a CEC column; however, zwitterionic stationary phases, which can make it possible to generate EOF with different directions for one column, are seldom investigated in CEC. In fact, there are many reports concerning chromatographic separation with zwitterionically modified materials, although it is still one of the new liquid chromatography separation modes studied in recent years. [3][4][5][6] Hu et al. 7 established the zwitterionic functionality via dynamically adsorbing the ODS (octadecyl silica) column with a sulfobetaine-type zwitterionic surfactant by the interaction between the C 18 groups on the surface and the hydrophobic tail of the surfactant. To overcome the drawback of inferior stability due to loss of functional moieties from the dynamically attached layer on the surface of stationary phases, ...

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“…Tramposch et al prepared a zwitterionic resin by reacting dimethylaminopropylsilane-modified silica with 1,3-propanesultone. They also showed that this stationary phase exhibits a weaker analyte adsorption, as compared to unmodified silica, when operated in the normal-phase chromatographic mode.…”

mentioning

confidence: 99%

Chromatographic Interactions between Proteins and Sulfoalkylbetaine-Based Zwitterionic Copolymers in Fully Aqueous Low-Salt Buffers

et al. 2000

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Macroporous monoliths containing N,N-dimethyl-N-methacryloyloxyethyl-N-(3-sulfopropyl)ammonium betaine (SPE) have been synthesized via in situ photopolymerization, yielding a stoichiometric balance between sulfur and nitrogen in the final polymer, which is indicative of a genuine strong/strong zwitterionic character. The chromatographic properties of these zwitterionic resins were evaluated with respect to the retention behavior of inorganic ions and proteins. The weak electrostatic nature of the interaction between the sulfobetaine monoliths and proteins provided a high selectivity between basic proteins and peptides. Elution was accomplished with low-ionic-strength fully aqueous mobile phases, whereby high recovery was obtained, even for hydrophobic proteins. Chaotropic ions such as perchlorate or thiocyanate were used as mobile phase modifiers to modulate the apparent ion exchange group density, thus introducing a route for the modulation of the ionic strength that is required to competitively elute the protein. The promising features of polymeric sulfoalkylbetaine interaction layers for separation and analysis of biological extracts was also manifested in an application involving purification of biologically active peptide-pheromone obtained from Enterococcus faecium.

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Polar bonded phase with the zwitterionic sulfobetaine functional group

Cited by 8 publications

References 7 publications

Suppression of Electroosmotic Flow and Prevention of Wall Adsorption in Capillary Zone Electrophoresis Using Zwitterionic Surfactants

Suppression of Electroosmotic Flow and Prevention of Wall Adsorption in Capillary Zone Electrophoresis Using Zwitterionic Surfactants

Monolithic Column with Zwitterionic Stationary Phase for Capillary Electrochromatography

Chromatographic Interactions between Proteins and Sulfoalkylbetaine-Based Zwitterionic Copolymers in Fully Aqueous Low-Salt Buffers

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