Development techniques forced-flow planar chromatography

Novel analytical techniques such as forced-flow planar chromatography (FFPC) and optimum pressure laminar chromatography (OPLC) are other additions to ever-refined tools for separation on a preparative scale, wherein small amounts of complex mixtures may be separated more efficiently on thin-layer chromatography plates operating at fast medium-pressure development with continuous collection of mobile phase at the end of chromatographic plates (Nyredy, 20(X), 2003). 

Forced-flow development. Forced-flow planar chromatography is a development technique wherein pressure is used to aid the mobility of the developing solvent. Examples of this are over-pressure layer chromatography (OPLC) and over-pressure thin-layer chromatography (OPTLC). In the latter a forced-flow technique is used to decrease the development time and thus speed up the separations. A pump controls the speed of the mobile phase. Theoretically, this method is faster than when movement of the solvent is due to capillary action alone (normal TLC) and can be used to advantage if slow-moving viscous solvents are involved as developing solvents. 

A technique that can achieve the maximum attainable resolution in TLC on a given separation distance without forced flow is automated multiple development (AMD). This step-gradient technique was developed by Burger. With respect to peak capacity the technique can be compared to HPLC, but it still maintains all benefits of planar chromatography. The heart of the instrument is a specially designed vacuum-tight chamber. Following sample application... 

OPLC, developed by Tyihdk et al. (3-6), is a forced-flow liquid chromatographic technique that combines the advantages of classical TLC, HPTLC, and high performance liquid chromatography (HPLC), and has provided many new possibilities in analytical planar chromatography. Although the many advantages of the technique would indicate it has considerable potential for preparative separations, there have so far been few publications on the subject. 

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