High performance planar chromatography, HPPLC Preparative anticircular chromatography (PACH) Sample collection Quantification Silica Gel (20X 20 and 10 X 10 cm) plates RP-18 (20 X 20 and 10 X 10 cm) plates Unsaponifiables from plant lipids Fatty acid methyl esters
Summary
A preparative anticircular chromatography (PACH) device was constructed to elucidate different applications of separation problems as well as to compare different sample collection techniques in this particular PLC mode. An anticircular PCapparatus had to beestablished whichallowed theutilization of 20 X 20 cm thin-layer plates as well as sampling positioning at any given radius. Typical solvent migration times were 8-1 2 minutesandca. 8-1 Omlof solvent was needed for an entire 20cm plate. It wasshownthat peakbroadeningeffectsduetodiffusion during long migration could be avoided in the same way as for analytical anticircular PLCon 10 X 10 plates. On theother hand, longer migration distances allow increased resolution, in turn allowing higher sample loads, particularly in the case of trace compound enrichment. A full descriptiori of the apparatus is given, including the sampling device.
Different sample collection techniques were tried and evaluated, including the through-flow technique by on-line center collection for plate washing as well as classical scraping-off of interesting zones. Further evaluation of the method included quantification and evaluation of consistency by UV/VIS scanning after spot-visualization. Several application examples are given to illustrate the efficiency of the preparative anticircular PLC-system.