Development techniques sandwich chambers

The possibility of zonal sample dosage in equilibrium conditions (after the front of mobile-phase and continuous-chromatogram development, which is provided by a horizontal sandwich chamber) was utilized by Glowniak et al. [3] in preparative chromatography of simple coumarins and furano-coumarins found in Archangelica fruits, performed with a short-bed continuous development (SB-CD) technique. 

This technique has other advantages compared with TLC and HPTLC, e.g. high-speed sample development, low consumption of eluant and reduced diffusion of analyte spots. Newman-Howells Associates and Supelco market horizontal sandwich chambers which are overpressurised in the latter system the chromatoplates can be eluted simultaneously from both ends, thus doubling sample throughput. 

The various PLC techniques were compared and trends in PLC summarized by Nyiredy (1996). The following recent applications for compound isolations by classic, capillary-flow PLC have been published photodegradation products of primaquine formed in an aqueous medium (Kristensen et al., 1993) synthesized isoprenoid diphosphates (20 mg of pure compound recovered from a single plate) (Kennedy Keller and Thompson, 1993) brain lipids (Deleva et al., 1992) components from aloe sap (0.75 mm layers of silanized silica gel and 0.5 mm of silica gel were developed in horizontal sandwich chambers) (Wawrzynowicz et al., 1994) taxol and cephalomannine from Taxus cuspidata (silica gel preparative plates developed with heptane-dichloromethane-ethyl acetate, 11 8 1) (Glow-niak et al., 1996) fenvalerate in a pesticide formulation (1-mm silica gel layers developed with hexane-acetone, 9 1, marker spots detected with o-dinitroben-zene-p-nitrobenzaldehyde reagent) (Gupta et al., 1996) and L-omithine-L-... 

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