Wall-coated open tubular column WCOT

Before discussing column preparation procedures a few comments on nomenclature are in order. Open tubular columns are also widely known as capillary columns. The characteristic feature of these columns is their openness, which provides an unrestricted gas path through the column. Thus open tubular colximn rather than capillary column is a more apt description. However, both descriptions appear frequently in the literature and can be emsidered interchangeable. The type of columns discussed so far are also known as wall-coated open tubular columns (WCOT). Here the liquid phase is deposited directly onto the column wall without the inclusion of any additive that might be considered as... 

The chromatographic column used was a wall-coated, open tubular column (WCOT) (J W Scientific) with a DB-1 Durabond chemically bonded stationary phase that had a nominal film thickness of 0.25 pm. The column was 60 m long X 0.32 mm i.d. The DB-1 stationary phase has chromatographic properties similar to SE-30. 

Wall-coated open tubular column (WCOT) liquid stationary phase on inside wall of column... 

One type of column is the wall-coated open tubular column (WCOT) in which the stationary phase is applied and bound directly to the walls of the column. Porous-layer open tubular columns (PLOT) are columns in which the stationary phase is deposited on fine particles of absorbent, absorbed on the walls of the column, increasing the available surface area of the column wall. Support-coated open tubular (SCOT) columns are those... 

Open tubular columns are simply capillary tubes in which the inside of the column wall is used as the support for the liquid phase. These wall-coated open tubular columns (WCOT) have the stationary phase distributed in the form of a thin film on the inside surface of the open capillary tube, the walls thus serving as the support. In order to reduce the thickness of the liquid phase film, a porous layer may be formed on the inside wall of the capillary tubing and then coated with the liquid phase to produce a support-coated open tubular column (SCOT). Porous-layer open tubular colunms (PLOT) are similar to SCOT colunms, the difference being that in the former, the stationary phase is deposited on fine crystalline particles or glass powder which is adsorbed onto the walls of the tube. In both cases, the available surface area of the wall is increased, and allows an increased amount of liquid phase to be accommodated in the same length and diameter of tubing. The whisker-walled (WW) colunm consists of whiskers chemically etched on the surface of the wall, which also result in a significant increase in the available surface area. Wall-coated, porous-layer, and support-coated capillary columns are all available as whisker-walled, i.e., WWCOT, WWPLOT, and WWSCOT, respectively. 

Two types of columns are used in SFC packed columns containing solid particles of small inner diameter or wall-coated open-tubular columns (WCOT), usually called just capillary columns. Packed columns have been preferred when capacity is the most relevant issue capillary columns are selected when efficiency is the goal. 

Wall-coated open tubular columns (WCOT columns), or simply capillary columns, and classical packed columns dominate the practice of gas-liquid chromatography today. Porous layer open tubular columns (PLOT columns) and classical packed columns dominate the practice of gas-solid chromatography. WCOT columns are typically up to 100 m... 

Wall-coated open tubular column (WCOT)... 

Walker carcinosarcoma 256, 993 Wall-coated open-tubular columns (WCOT), 1074 Walnuts, 1736... 

Open tubular or capillary columns have open unrestricted path for the gas within the column. These columns are about 15-30 meters in length with an inside diameter of about 0.25 mm. The inner wall of these columns is coated with the liquid stationary phase to about 1 m in thickness. The open tubular columns are of two kinds. One is known as the wall coated open tubular column [WCOT) in which the liquid phase is coated on the column wall. These columns have limited sample capacity and are unsuitable for large-scale separations. The second type is known as support coated open tubular columns (SCOT). In these columns a porous layer is formed on the inside wall of the tubing. The porous layer can either be formed by chemical treatment of the inner wall or is deposited on the inner wall. The support is coated in such a way that the inherent property of the capillary columns, i.e., the unrestricted gas flow is retained. The inert porous layer is then impregnated with the liquid stationary phase. These columns have a higher sample capacity. 

PLOT. An acronym for porous-layer open tubular column, which is an open tubular column with fine layers of some adsorbent deposited on the inside wall. This type of column has a larger surface area than does a wall-coated open tubular column (WCOT). 

Column Material. If a capillary column is to be used, fused silica is the material of choice. A number of fused-silica capillary columns are available. The wall-coated open-tubular column (WCOT), where the liquid stationary phase is coated on the deactivated inside wall of the capillary, has become the most widely used type of capillary column. A second type of capillary column is the porous-layer open-tubular column (PLOT), in which the stationary phase consists of solid particles coated on the deactivated inside wall of the capillary. A third type of capillary column is the support-coated open-tubular column (SCOT), in which the liquid stationary phase is coated over the solid particles coated on the deactivated inside wall of the capillary. 

WCOT. Wall Coated Open Tubular column. 

WCOT Columns. Wall-coated open tubular columns wherein the internal wall is coated with a thin layer of liquid (liquid substrate). ... 

WCOT wall-coated open tubular (column)... 

URL USEPA UV WCOT WWW uniform resource locator United States Environmental Protection Agency ultraviolet wall-coated open tubular (column) World Wide Web... 

WCOT Wall coated open tubular columns... 

The original capillary column, invented and patented by Dr. Marcel Golay [1], consisted of a tube with a thin film of liquid phase coated on the inside surface. This is properly called a wall-coated open tubular column or WCOT, shown in Figure 6.2. The tube can be made of fused silica, glass, or stainless steel. Almost all commercial capillary columns are now made of fused silica. 

WCOT. An acronym for wall-coated open tubular column. It is a capillary column in which the inside wall is coated with the stationary phase. 

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