Forced-Flow Planar Liquid Chromatographic Techniques (After Twenty-Two years)

In the twenty-two years since a similar review in the first issue of this journal there has been much progress in forced-flow planar liquid chromatography (FFPLC). Innovative developments have resulted in extremely diverse new technical solutions. This review briefly summarizes techniques which are already in use as a result of this progress (overpressured-layer chromatography, OPLC, and rotation planar chromatography, RPC) and the future potential of other FFPLC techniques, for example electrochromatographic techniques and shear-driven chromatography (SDC). It seems that efforts in FFPLC provide real possibilities of efficient analytical and preparative separations of different complex mixtures exploiting, with increasing success, the objective advantages of planar layer chromatography. This review summarizes, first, the unique opportunities resulting from modern biological detection on the adsorbent layer (BioArena) and some recent results obtained. These results include — among others — the indirect detection of small key molecules (e.g. formaldehyde, HCHO, and ozone, O3) in chromatographic spots. Practical applications are mainly in-vivo investigations — already without chromatographic separations — with special emphasis on disease resistance and cell proliferation. It seems, however, that in the future BioArena-guided in-vivo investigation will enable characterization of biologically active substances.