https://doi.org/10.1351/goldbook.P04682
A separation technique in which the stationary phase is present as or on a plane. The plane can be a paper, serving as such or impregnated by a substrate as the stationary bed (paper @C01075@, PC) or a layer of solid particles spread on a support e.g. a glass plate (thin layer @C01075@, TLC). Sometimes planar @C01075@ is also termed open-bed @C01075@.
Source:
PAC, 1993, 65, 819. (Nomenclature for chromatography (IUPAC Recommendations 1993)) on page 825 [Terms] [Paper]