PubMed · 8798201
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
S Doonan. 1996. Chromatography on hydroxyapatite.. https://doi.org/10.1385/0-89603-336-8%3A211
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Novel equations (Guillaume Y. C.; et al. Anal. Chem. 2000, 72, 853) were developed to describe the large double-stranded DNA molecule retention in slalom chromatography (SC). These equations were applied for the first time to model both the "apparent selectivity" and the resolution between two eluted DNA fragments on a chromatogram. A study of the column efficiency corroborated the fact that slalom chromatography is not based on an adsorption or equilibrium phenomenon, but can be attributed to a hydrodynamic phenomenon. Using a combination of the dynamics of DNA fragment progression in the column and fractal considerations, it was shown that the apparent selectivity depends both on the DNA fragment sizes and mobile-phase flow rate and therefore a balance between two hydrodynamic regimes. A chromatographic response function was also used to obtain the most efficient separation conditions for a mixture of DNA fragments in a minimum analysis time. The chromatographic data confirmed that in SC the flow rate can increase or maintain the separation efficiency with an associated decrease in the analysis time. This constitutes an attractive outcome in relation to the classical chromatographic separation.
Electrochromatography employs an axial electric field across a chromatographic stationary phase to separate proteins and other molecules based on differences in electrophoretic mobility. Because the separation is electrically driven, the need for additional chemical reagents is reduced. Two major impediments to scale-up of electrochromatography columns, removal of heat and electrolysis gases, have historically limited the diameter of packed columns to 2.5 cm ID with volumes of approximately 55 mL. We report a novel electrochromatography column that effectively removes electrolysis gases and minimizes heating. A vital component of this system is a new electrode design that couples a platinum gauze with an ultrafiltration membrane across both ends of the column. Use of a methacrylate base stationary phase enabled axial voltage gradients of 10 to 20 V/cm. Thermocouples inserted radially in the column at four axial positions showed that the flow of a 4 degrees C mobile phase coupled with heat conduction through the column walls controlled the temperature to 28 degrees C. The new column design, with dimensions of 3.81 cm ID x 38.1 cm long and bed volume of 400 mL, was demonstrated by separating mixtures of BSA and myoglobin. The column was operated in a horizontal position with radial sample injection and withdrawal at the ends of the packed bed. These experiments are a first step in demonstrating that scale-up of electrochromatography columns can be achieved by choosing appropriate flow rates, voltage gradients, and stationary phase.
Mitsunobu reaction of an alcohol ROH with a carboxylic acid, phthalimide, or N-hydroxyphthalimide (NuH) using DNAD (4) and (diphenylphosphino)polystyrene (11) gave the products RNu. Ring-opening metathetic polymerization of the side product DNADH(2) (3) using Cl(2)(Cy(3)P)(2)Ru=CHPh (13) and filtration, to remove poly(DNADH(2)), (diphenylphosphino)polystyrene 11, its oxide, and its adduct with excess DNAD, gave RNu (43-100%, 86-96% purity) without recourse to chromatography.