PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 12134808

Aqueous chromatography utilizing hydrophobicity-modified anionic temperature-responsive hydrogel for stationary phases.

Jun Kobayashi·Akihiko Kikuchi·Kiyotaka Sakai·Teruo Okano
View original source ↗Export metadata ↓

Abstract

A new pH-/temperature-responsive poly(N-isopropylacrylamide-co-acrylic acid-co-N-tert-butylacrylamide) (poly(IPAAm-co-AAc-co-tBAAm)) hydrogel grafted on silica beads was evaluated as column matrix for a cation-exchange thermoresponsive chromatography. The stationary phase showed simultaneous changes in temperature-responsive surface charge density and hydrophobicity by incorporation of anionic AAc and hydrophobic tBAAm into IPAAm sequences. Thermoresponsive polymer property alterations were confirmed by temperature-responsive phase transition and shift in apparent pKa values. Catecholamine derivatives were retained on poly(IPAAm-co-AAc-co-tBAAm)-modified column at pH 7.0. Analyte retention was primarily due to the electrostatic interaction. It was noted that the temperature-induced phase transition of poly(IPAAm-co-AAc-co-tBAAm) hydrogel layer on the stationary phases was evidenced by the apparent inflection point in van't Hoff plots around 36 degrees C. This suggests that solute interactions should be changed below and above the stationary phase transition temperature, reducing electrostatic interaction above the transition temperature.

Explore related subjects

AnionsChromatography, LiquidHydrogel, Polyethylene Glycol DimethacrylateStatic ElectricityJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Jun Kobayashi, Akihiko Kikuchi, Kiyotaka Sakai, Teruo Okano. 2002-06-07. Aqueous chromatography utilizing hydrophobicity-modified anionic temperature-responsive hydrogel for stationary phases.. https://doi.org/10.1016/s0021-9673(02)00388-6

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Purification of cell culture-derived human influenza A virus by size-exclusion and anion-exchange chromatography.

A process comprising of size-exclusion chromatography (SEC) and anion-exchange chromatography (AEC) was investigated for downstream processing of cell culture-derived influenza A virus. Human influenza virus A/PR/8/34 (H1N1) was propagated in serum-free medium using MDCK cells as a host. Concentrates of the virus were prepared from clarified and inactivated cell culture supernatants by cross-flow ultrafiltration as described before. SEC on Sepharose 4 FF resulted in average product yields of 85% based on hemagglutination (HA) activity. Productivity was maximized to 0.15 column volumes (cv) of concentrate per hour yielding a reduction in total protein and host cell DNA (hcDNA) to 35 and 34%, respectively. AEC on Sepharose Q XL was used to separate hcDNA from virus at a salt concentration of 0.65 M sodium chloride. Product yields >80% were achieved for loads >160 kHAU/mL of resin. The reduction in hcDNA was 67-fold. Split peak elution and bimodal particle volume distributions suggested aggregation of virions. Co-elution with hcDNA and constant amounts of hcDNA per dose indiciated association of virions to hcDNA. An overall product yield of 52% was achieved. Total protein was reduced more than 19-fold; hcDNA more than 500-fold by the process. Estimation of the dose volume from HA activity predicted a protein content at the limit for human vaccines. Reduction of hcDNA was found insufficient (about 500 ng per dose) requiring further optimization of AEC or additional purification steps. All operations were selected to be scalable and independent of the virus strain rendering the process suitable for vaccine production.

Anions↗
PubMed2007

On the quality of the hardness kernel and the Fukui function to evaluate the global hardness.

An approximated hardness kernel, which includes the second derivative with respect to the density of the kinetic energy, the electron-electron coulomb repulsion, and the exchange density functionals, has been tested for the calculation of the global hardness. The results obtained for a series of 40 cations and neutral systems and 16 anions represent in most cases an improvement of the results obtained using the HOMO-LUMO gap approach and indicate the viability of this approach to evaluate global hardness. In addition, the relevance of the Fukui function approximation and the role of the three components of the hardness kernel in the evaluation of the global hardness have been analyzed.

Anions↗
PubMed2007

Development of cation/anion "interaction" scales for ionic liquids through ESI-MS measurements.

Electrospray ionization mass spectrometry applied to ionic liquids allowed the study of loosely bonded supramolecules, originating from these organic salts. Based on the observation that ionic liquids formed cationic [C(q+1)X(q)](+) and anionic [C(q)X(q+1)](-) supramolecular aggregates, we have investigated mixed networks, formed by different cations coordinated to a selected anion or by different anions bonded to a given cation, i.e., [C1...X...C2](+) and [X1...C...X2](-), with the aim to build a scale of the cation-anion interaction strength. The qualitative order of intrinsic bond strength to Br- was found to be the following: [emim](+) > [bmim](+) > [mor1,2](+) > [hmim]+ > [omim](+) > [mor1,4](+) > [bupy](+) > [bpyrr](+) > [picol](+) > [bm(2)im](+) > [TBA](+). Similarly, the interaction energies to 1-butyl-3-methylimidazolium (bmim) species envisaged two classes of anions: species tightly coordinated to the cationic moiety that include CF3COO(-), Br(-), N(CN)2(-), and BF4(-) and anions loosely interacting with the alkylimidazolium species such as OTf(-), PF6(-), and Tf2N(-).

Anions↗