Colloidal particle chromatography

Figure 1, Classification of principal areas of colloidal particle chromatography...

Small, H., Hydrodynamic chromatography - A technique for size analysis of colloidal particles , J. Colloid Interface Sci., 48, 147-161 (1974). 

In recent years particle chromatography has developed dramatically as a simple and versatile method for particle size determination. The size fractionation of colloidal particles by chromatograph-... 

In Fl-FFF, the channel is created by placing a mylar spacer with the channel cut out between two porous frits. A membrane hlter of a specihc molecular weight cutoff is placed on one of the frits and acts as the accumulation wall to permit flow, without loss of particles. The applied force is then a perpendicular flow of the carrier solution across the porous frits. Fl-FFF is a versatile technique capable of separating macromolecules as small as roughly 1000 Da, in which case it is comparable to gel permeation (size exclusion) chromatography. However, Fl-FFF can also be applied to the separation of colloidal particles. In this case the hydrodynamic diameter of the colloidal particle is related to the retention volume, V by the equation... 

Hydrodynamic chromatography (HDC) offers a means of obtaining size information on colloidal particles in suspension with the same ease that is characteristic of chromatographic methods for size analysis of molecules in solution. 

Protoporphyrin IX dissolved in water at pH 9 and formed molecular assemblies at pH 4.5 near the pKa of the propionic acid groups. Gel chromatography showed that the colloidal particles have molecular weights above 10. A particular characteristic is the splitting of the Soret band with broad peaks at 360 and 450 nm. Electron micrographs, however, showed no characteristic supramolecular structures of the unstable colloidal particles. ... 

Several research techniques (ultrafiltration, gel chromatography, electrophoresis, etc.) may be used to separate colloidal particles and will help to add to knowledge on this subject. It is also possible to... 

Morphology control is indispensable in many of the advanced applications envisioned for functional mesoporous materials (54, 267). Permselective membranes, micro-spheres, or monoliths are important for sorption, separation, and chromatography purposes. Porous thin films or fibrous structures are relevant for electronics, optics, low fe-dielectrics, and sensing applications. Colloidal particles or nanospheres are preferred for biomedical systems to be used in drug delivery or magnetic resonance imaging (MRl) with contrast agents. 

Monodisperse colloidal silica spheres with various surface coatings are of considerable interest to many fields, such as ceramics, colloids, catalysis, chromatography, and glass preparation. We are interested in these particles for their... 

Fig. 19.38 When water samples collected at different depths in Lake Hoare in Taylor Valley are acidified prior to analysis by ion chromatography, the measured calcium concentrations are about two times higher than in unacidified samples. The effect is caused by the displacement of Ca "" by from negatively charged sites on the surface of suspended colloidal particles (Adapted from Welch et al. 1996)...

In most cases, separations of colloidal particles by exclusion chromatography have been carried out with long columns of relatively large porous particles. Work with such systems requires long separation times and provides only modest resolution as a result of low column efficiency. 

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