Diatomite supports, properties

The purpose and role of the solid support is the accommodation of a uniform deposition of stationary phase on the surface of the support. The most commonly used support materials are primarily diatomite supports and graphitized carbon (which is also an adsorbent for GSC), to a lesser extent. Teflon, inorganic salts and glass beads. There is no perfect support material because each has limitations. Pertinent physical properties of a support for packed-column GC are particle size, porosity, surface area, and packing density. Particle size impacts column efficiency via the A term or eddy diffusion contribution in the van Deemter expression (Equation 2.44). The surface area of a support is governed by its porosity, the more porous supports requiring greater amounts of stationary phase... 

Diatomaceous earth has been used as a chromatographic support since the inception of gas chromatography. A diverse line of products are available. The high surface area and stmcture of diatomite enables it to carry the Hquid phase while an inert surface prevents interference with partitioning. Properly treated diatomite chromatographic supports make use of all its unique properties (10). 

An ideal support would act like a sponge, holding the liquid phase as a thin film, without playing any further role in the separation process. Although no such ideal support exists, the diatomaceous earths provide a reasonable compromise of properties (Table 3). Diatomite (diatomaceous earth) is composed of the skeletons of diatoms, single-celled algae, which have accumulated in large beds in various parts of the... 

Other uses - Diatomite is used as a nonscratching abrasive in polishes and cleansers, in concrete, mortars, grouts, plasters, and stucco for improved plastic and cured properties, in asphalt products to decrease cracking caused by rapid temperature changes, in catalyst carriers, in chromatographic supports, and as a silica source in the production of synthetic calcium and magnesixun silicates. 

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