PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 16524096

Flow gradient liquid chromatography using a coated anion exchange microcolumn.

Ekaterina P Nesterenko·Leon P Barron·Pavel N Nesterenko·Brett Paull
View original source ↗Export metadata ↓

Abstract

Ion chromatography on a 4.0-mm-long (3.0 mm ID) ion exchange column is presented. Using a 10 mM phosphate buffer (pH 2.22) the separation of up to six UV-absorbing anions was obtained using the microcolumn, containing 5 microm RP support (Phenomenex Gemini) coated with the zwitterionic surfactant, (N-dodecyl-N,N-dimethylammonio) undecanoate. The short analytical column facilitated the application of a flow gradient programme over the flow range 0.3-5 mL/min resulting in optimum resolution of nitrite, nitrate, benzoate, iodide, thiocyanate and trichloroacetate in less than 10 min. The effect of both eluent concentration and pH on the retention of six selected anions was investigated, showing a strong pH capacity dependence. The microcolumn was found to exhibit no selectivity towards chloride and so was well suited to the analysis of saline samples. To illustrate this, the rapid analysis of a concentrated iodized table salt sample (20 g/L) was carried out. Following standard addition, a concentration of 3.55 +/- 0.05 microg iodide/g and 1.05 +/- 0.02 microg iodate/g in the solid salt sample was determined.

Explore related subjects

AnionsBuffersChromatography, Ion ExchangeFatty AcidsHydrogen-Ion ConcentrationIodidesOsmolar ConcentrationQuaternary Ammonium CompoundsSodium ChlorideSurface-Active AgentsJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Ekaterina P Nesterenko, Leon P Barron, Pavel N Nesterenko, Brett Paull. 2006. Flow gradient liquid chromatography using a coated anion exchange microcolumn.. https://doi.org/10.1002/jssc.200500335

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↗