Rotation planar chromatography chamber type

A series of instruments for rotation planar chromatography have been described. These are based on the work of Hopf [61 ], more than 50 years ago, who introduced an apparatus in which the mobile pha.se was propagated by centrifugal forces. Subsequently methods have been developed by a number of researchers to control the mobile phase movement (for review, see [62 ). The separation can be performed in various types of chambers, such as in a normal chamber, a microchamber, or an ultramicrochamber. The separation takes place during constant rotation and the flow rate of the mobile phase changes throughout, i.e. the flow rate is inversely proportional to the square distance from the centre of the supply. 

Rotation planar chromatography (RPC), as with OPLC, is another thin-layer technique with forced eluent flow, employing a centrifugal force of a revolving rotor to move the mobile phase and separate chemical compounds. The RPC equipment can vary in chamber size, operative mode (analytical or preparative), separation type (circular, anticircular, or linear), and detection mode (off-line or online). The described technique was applied in analytical and micropreparative separation of coumarin compounds from plant extracts. 

Chamber types for rotation planar chromatography (RPC) differ according to the vapor space in N-RPC, the layer rotates in an unsaturated N-chamber in M-and U-RPC (Nyiredy et al., 1988b), the chamber is the saturated (M) and unsaturated (U) sandwich type (Nyiredy, 1992). In the M (micro)-chamber, the plate... 

The main difference between the chamber types used in rotation planar chromatography (RPC) (42-44) lies in the size of the vapor space, which is an essential criterion in RPC (43). Therefore, an additional symbol indicates the vapor space [normal chamber, microchamber, ultramicrochamber, and column RPC (N-RPC, M-RPC, U-RPC, and C-RPC respectively)). 

Mobile-phase velocity is higher with forced-flow development than in capillary-flow TLC. The actual flow rate is influenced by the type of chamber (rectangular or sandwich, saturated or unsaturated), the pressure and solvent viscosity (OPLC), or the rotational speed (RPC) (Nyiredy et al., 1988a). Nyiredy (1992) discussed the relation among resolution, separation distance, and time for forced-flow planar chromatography compared to capillary flow. It was stated that for separation of nonpolar compounds by FFPC on silica gel, a separation time of 1—2.5 min over a separation distance of 18 cm can be used without great loss in resolution. By contrast, longer separation times are needed for separation of polar compounds. 

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