Glass developing chambers

Detection with iodine vapor is one of the most widely applicable visualization techniques. If iodine crystals are placed in the bottom of a covered glass development chamber, within a few hours the atmosphere in the chamber will be saturated... 

Figure 7.3 Glass developing chambers for TLC and HPTLC. (Photograph courtesy of Analatech.)...

Chromatographic development chambers for analytical pirrposes are commercially available in several different sizes. The most commonly used ones are rectangiflar glass tanks with inner dimensions of 21 X21 X9 cm, and they can be used to develop two plates simultaneously in the preparative scale. Even bigger tanks are available for much larger plates, for preparative layer chromatography. The width of the chamber should be varied depending on the size and the number of plates to be developed. 

Instead of a microscope slide, you usually use a 12 X 12-in. glass plate and coat it with a thick layer of adsorbant (0.5-2.0 mm). Years ago, I used a small paintbrush to put a line (a streak rather than a spot) across the plate near the bottom. Now you can get special plate streakers that give a finer line and less spreading. You put the plate in a large developing chamber and develop and visualize the plate as usual. 

Lagally et al. [74] developed an integrated device for PCR and NCE with electric field control and fluorescence detection. Furthermore, the device had integrated heaters and temperature sensors, as well as PDMS membrane valving to control analyte transport. The PDMS unit was fabricated as membrane valves between a glass PCR chamber and the glass NCE channel, allowing precise control of both process unit operation and analyte transport. 

Developing Chamber A glass chamber that can accommodate one or more plates and can be properly closed and sealed. It is fitted with a plate-support rack that can support the plates when the lid of the chamber is in place. 

The H-separation chamber (DESAGA), a mini horizontal development chamber (Fig. le), is made of solvent resistant PTFE (1) covered with a sheet of glass (2) 4 mm thick. The HPTLC plate (5X5 cm) is laid down for development with the thin layer underneath (3). The mobile phase from the trough (4) is led by a glass frit rod (5) to the thin layer of sorbent. The groove in which the frit rod sits ensures... 

In the early days of TLC, before the advent of HPLC, researchers experimented in their laboratories with developing chambers of glass, sometimes V4A steel or, for less aggressive solvent systems, plastics. Various chambers were used for the following purposes ... 

To line a double-trough chamber, two sheets of CS paper are cut to size and fitted in the troughs, and the developing chamber is tilted forward so that one sheet rests on the front wall and the other can be held onto the back wall with thumb and forefinger. Approximately half of the solvent system to be used is now carefully poured onto the front glass wall over the paper and into the front trough. Care must be taken to avoid the formation of any air bubbles between the paper and the wall of the chamber. The chamber is then turned through 180° and carefully tilted forward, and the operation is repeated. 

Sandwich chamber (narrow developing chamber for vertical development in which the TLC plate is fixed to a second glass plate)... 

Figure 5.2 Developing chamber and TLC plate. Left, available in a variety of dimensions according to the size of the plates (of 5 x 5 to 20 x 20 cm), the chambers are made of glass and equipped with a tight fitting cover. Right, typical appearance after the TLC plate is partially dry. A faint line can be observed at the location of the solvent upper limit. This line is called the solvent front. Calculation of Rf (cf. paragraph 5.4). A substance that does not migrate from the sample origin has a / f = 0.

The apparatus is quite simple. It consists of an 8 oz glass jar, that serves as the developing chamber, and a 5 cm... 

It is not essential to use a tank at all. A sandwich can be made consisting of a second glass plate clamped firmly over the sorbent surface (Figure 3.8). This sandwich can then be placed into a normal development chamber or into a special trough designed to prevent solvent loss. 

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. 

Fig. 10 Horizontal developing chamber (Camag). 1 HPTLC plate (layer facing down), 2—glass plate, 3—reservoir for developing solvent, 4— glass strip, 5—cover plate, 6—conditioning tray.

Twenty miCToliters of irradiated and control difloxacin solutions were applied using a Linomat V (CAMAG, Switzerland) sample applicator as 8-mm bands. Chromatograms were developed to a distance of 95 mm immediately after its preparation in a glass chromatographic chamber (18 x 9 x 18 cm in size). The plate was dried at room temperature for 30 min. 

To execute a TLC analysis, a small amount of the sample to be analyzed, or a solution of it, is first applied to a solid adsorbent bound to a rectangular glass or plastic plate (Fig. 6.2a). The adsorbent serves as the stationary phase. Next, the plate, with its spotted end down, is placed in a closed jar, called a developing chamber (Fig. 6.3). The chamber contains a saturated atmosphere of a suitable eluant or eluting solvent, which is the mobile phase and may be comprised of either a single solvent or mixture of two or more. A folded filter paper is often used to help maintain solvent equilibration in the chamber. It is important that the level of... 

Chambers for horizontal development can be constructed from simple materials. For example, as in Fig. 33, one can place the solvent in a shallow glass developing or instrument dish. A glass strip or rod (2 cm diameter), round which filter paper has been wrapped several times, serves to transport solvent to the layer. A glass rod or tube forms the second support. This and similar devices ensure good chamber saturation. Lees et al. [389] have accomplished continuous development... 

Fig. 40. Small basic equipment for TLC including a simple spreader for coating glass plates with a 250 [xm layer and for grooved glass plates. A small development chamber for the 10 x 15 cm plates is in the left background (photograph from Firm 44)...

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