Rectangular glass tanks

Development of plates. Individual 20 x 5 cm plates are conveniently developed in a cylindrical glass jar (Fig. 2.133) (Shandon). Larger plates, 20 x 10cm and 20 x 20 cm, require a rectangular glass tank of suitable dimensions such as that shown in Fig. 2.134 such a tank can also be used to allow the simultaneous de-... 

A. Rectangular glass tanks (N-tanks) A rectangular glass tank is often uSed in TLC to develop 20 x 20 cm TLC plates (Fig. 5.2). Popular models have inner dimensions of 21 X 21 X 9 cm and can accommodate two plates using 50-100 ml of solvent to fill the tank to a depth of 5 mm. The tank is lined on three sides with thick filter paper that is thoroughly soaked with the solvent. The tank should be allowed to stand for 30-60 min to allow the inside atmosphere to saturate with solvent vapor... 

Preparative-scale plates are usually developed in rectangular glass tanks (e.g. 21 x 21 X 9 cm) lined with thick filter paper on all sides. The chamber is charged with sufficient mobile phase for the development step, and to soak the filter paper liner. Equilibration of the vapor phase typically requires 1 -2 h. Saturated developing chambers are preferred to minimize the formation of irregular solvent fronts and developed sample bands. The plates are usually inserted in a rack that holds them in a vertical position, and allows several plates to be developed simultaneously. Ascending development typically requires 1-2 h for a solvent-front migration distance of 18 cm. 

Develop the sheet in 100 ml of the mobile phase in a saturated rectangular glass tank. Development time at room temperature will be 60 to 90 min. 

Develop in separate rectangular glass tanks lined with Whatman No. 1 filter paper and equilibrated with the respective mobile phases for 15 min before inserting each layer. Wrap the tanks with aluminum foil to exclude light. Leave a small opening in the foil to observe the solvent front. Develop the silica gel for a dis-... 

Develop the plate in a rectangular glass tank lined with paper and allowed to equilibrate with the mobile phase for 10 min prior to inserting the layer. Allow the plate to develop for a distance of 13.5 cm past the origin (sorbent-preadsorbent interface). Development time will be approximately 3.5 h. 

Whereas many chromatographic chambers (e.g., sandwich, Vario-KS, Horizontal, BN-, U-, N-chamber) (17) are available for analytical TLC separations, the rectangular glass tank, or N-... 

Development is usually performed in rectangular glass tanks lined with filter paper. One hundred milliliters of solvent is a convenient volume in a 21 x 21 x 6 cm tank. After an equilibration period of 20 min, the plate is placed in the tank and allowed to stand until the desired developing distance is obtained. 

Although a Chromarod developing tank may be provided with the analyzer, any regular rectangular glass TLC tank can be used for development as long as the Chromarod rack fits (e.g., 20 x 20-crn). 

Use rectangular glass N-tanks in each case. Develop organochlorines in a paper-lined, saturated tank until the mobile phase reaches the top of the plate. Develop OP pesticides and carbamates in unsaturated tanks for a distance of 10 cm above the origin. 

The raw materials are melted at temperatures of 1200 to 1600°C in tank, cupola, electric arc or electrical melting units. Tank furnaces similar to those used for the manufacture of glass are used for the production of glass wool. The melt vessel is a large rectangular tank with the mixture added at one end and the melt taken off at the other. 

B. Sandwich chambers (S-chambers) The sandwich chamber is very thin to accommodate a single 20 X 20 cm plate and minimal solvent for ascending chromatography. S-chambers with a plain glass cover plate are considered unsaturated, whereas saturated conditions are achieved by employing a counter plate coated with sorbent (often cellulose) and soaked with solvent. S-chambers offer advantages over rectangular tanks, that is, faster gas-phase equilibration and excellent reproducibility both due to the much smaller internal volume when compared with N-tanks [51]. 

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