Open tubular column metal

Numerous materials have been used to fabricate open tubular columns. Most early studies were conducted using stainless steel tubing and later nickel tubing of capillary dimensions [147-149]. These materials had rough inner surfaces (leading to non-uniform stationary phase films), metal and oxide impurities at their surface which were a cause of adsorption, tailing, and/or decomposition of polar solutes and because their walls were thick, thermal Inertia that prevented the use of fast temperature programming. None of these materials are widely used today. 

In open tubular columns, the stationary phase is held on the inner surface of a capillary, whereas in packed columns, the stationary phase is supported on particles that are contained in a glass or metal tube. Open tubular columns contain an enormous number of plates that permit rapid separations of closely related species. They suffer from small sample capacities. 

Silani/cd surfaces of column packings may still show a residual adsorption, which apparently occurs with metal oxide impurities in the diatomaecous earth. Acid wa.shing prior to silaniTtaliun removes these impurities. Fused siliea used for manufacturing open tubular columns is largely free of this type of impurity. Beeausc of this, fewer problems with adsorption arise with fuscd-silica columns. 

The development of the flexible fused silica capillary GC column described in Section 11.5 resulted in the domination of the GC market by open tubular columns and instruments tailored to their use. Packed columns are relegated to a few special applications. Fused silica capillaries were easy to install. They were more inert (i.e., contained less active sites causing tailing) than glass or metal capillaries or the particle supports used in packed column GC. Even when the resolution of packed columns was sufficient for simple separations, a capillary coated with the same stationary phase could... 

Fused silica columns have greater physical strength and flexibility than glass open tubular columns and are less reactive toward analytes than either glass or metal columns. 

Support coated open tubular (SCOT) columns, 4 615 6 379 Supported liquid membranes, 16 28 Support material, in fluidized-bed encapsulation, 11 540 affinity chromatography, 6 392-393 chromatography, 6 375 gas chromatography, 6 375 Supported metals... 

I. Nukatsuka, S. Osanai, K. Ohzeki, Preparation of open tubular solid-phase extraction column with 5-amino-8-hydroxyquinoline-modified gold nanoparticle phase for the enrichment of heavy metal ions, Anal. Sci. 24 (2008) 267. 

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