Developing chambers horizontal

After a chromatogram has been developed the TLC plate is removed from the developing chamber and the status quo is fixed by removing the mobile phase remaining in the layer as quickly as possible. This is properly performed in the fume cupboard so as not to contaminate the laboratory with solvent fumes. If possible the TLC plate should be laid horizontally because then as the mobile phase evaporates the separated substances will migrate evenly to the surface where they can be the more readily detected. A fan or hair dryer (hot or cold air stream)... 

A horizontal developing chamber is also manufactured by CAMAG for plates 10 X 10 cm and 20 X 10 cm [13]. Its application is reported in the literature for analytical separations. Therefore, it is not described here in detail. 

The horizontal developing chamber is a sandwich-type chamber for the. simultaneous development of samples from both ends toward the plate center, or for conventional edge-to-edge development [194]. The mobile phase is transported from the reservoir to the... 

The anticircular development chamber contains many of the features. found in the D-chamber. The plate is developed horizontally, the chamber volume is small, and the vapor phase can be controlled by external means [111]. An outer circle is cut fron... 

Related to the linear development chamber is the Vario-KS chamber [8,195]. The plate is also developed in the horizontal position in a sandwich configuration. However, this chamber is... 

Figure 10.6. Developing chambers for plane chromatography (a) descending— used with PC (b) ascending—used with TLC and PC (c) sandwich—used with TLC (d) horizontal—used with paper as shown, but also adaptable for HPTLC.

Serotonergic anxiolitics were investigated for their purity control by HPTLC and UV scanning densitometry (1321. A horizontal developing chamber from Camag (Muttenz, Switzerland) was used and the separations were done on 200 x 100 mm silica gel 60 F254 HPTLC plates. Separation characteristics of the anxiolitics and their impurities are given in Table 10.19. 

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... 

Figure 33-4 (a) Ascending-flow developing chamber, (b) Horizontal-flow developing chamber, in which samples are placed on both ends of the plate and developed toward the middle, thus doubling the number of samples that can be accommodated. 

In the DAB method, the identity test for camomile flowers is also performed using chloroform p.f.a. (DAB nomenclature chloroform R) as the solvent. Even the very low percentage of water in the stabilizer present (ethanol) can lead to the formation of a (3-front on development (Fig. 44a). If, on the other hand, the chloroform is dried over sodium sulfate shortly before placing it in the developing chamber, a thin-film chromatogram without an interfering (3-front is obtained, as shown in Fig. 44b [46]. This example could not be repeated reproducibly, and probably only happens with the 5 x 5cm horizontal chamber (see Section 4.2.1.2). 

With developing chambers for horizontal development, the chamber type again determines the price. 

A different manufacturer (CAMAG) produces two horizontal developing chambers for the plate sizes 10 x 10 cm and 20 x 10 cm, mainly for use with HPTLC plates. These types of chamber enable the samples to be developed from the two opposite sides towards the middle, giving an available migration distance of only 4.5 cm. With optimal operation, ca. 70 samples can be analyzed in parallel on the 20 X10 cm plate. These developing chambers are mainly used where a large number of samples must be analyzed quantitatively in a short time. However, this type of chamber is not suitable for use at low temperatures, as in this case hquid can easily condense out and cause problems. Hie price per set of equipment is over 100 DM. 

Developing chambers for horizontal development were originally conceived as sandwich chambers (S-chambers) in which the plate, with the layer imdemeath, is placed above the counter-plate at a distance of 0.5 mm. Without this counter-plate, a filter paper soaked in solvent can be placed at the bottom of the chamber, enabling development to be performed in a saturated chamber. Chromatography can be performed with only a few ml solvent in horizontal chambers, which is, of course, economic and reduces disposal problems. However, the question arises how much of a four- or five-component solvent system is actually used if only 2 ml is consumed in the development process in the 5 x 5 cm horizontal chamber ... 

During development, the development chamber should be standing on a flat, horizontal surface and should be left completely undisturbed. 

The chamber type is noted N for normal chamber (or DT-N for double-trough chamber, CAMAG), H for horizontal chamber (e.g. 5x5 cm, DESAGA), DC-MAT for automatic development chamber (Baron), ADC for automatic developing chamber (CAMAG), etc. 

Developing chamber for horizontal development Homeopathic Pharmacopoeia (Homoopathisches Arzneibuch)... 

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