A review of advances in two-dimensional thin-layer chromatography

Planar chromatography - Current practice and future prospects

Planar chromatography, in the form of thin-layer or high-performance thin-layer chromatography (TLC, HPTLC), continues to provide a robust and widely used separation technique. It is unrivaled as a simple and rapid qualitative method for mixture analysis, or for finding bioactive components in mixtures. The format of TLC/HPTLC also provides a unique method for preserving the separation, enabling further investigation of components of interest (including quantification/structure determination) separated in both time and space from the original analysis. The current practice of planar chromatography and areas of development of the technology are reviewed and promising future directions in the use of TLC/HPTLC are outlined.

Macroporous Polymer Monoliths in Thin Layer Format

Nowadays, macroporous polymer monoliths represent widely used stationary phases for a number of dynamic interphase mass exchange processes such as high-performance liquid chromatography, gas chromatography, electrochromatography, solid-phase extraction, and flow-through solid-state biocatalysis. This review represents the first summary in the field of current achievements on the preparation of macroporous polymer monolithic layers, as well as their application as solid phases for thin-layer chromatography and different kinds of microarray.

Application of targeted 2D planar chromatography in the control of ginkgolic acids in some herbal drugs and dietary supplements

Two-step targeted 2D planar chromatographic method (2DTLC) was used in the determination of ginkgolic acids in pharmaceuticals and dietary supplements. The choice of the extraction method and the separation technique was guided by the formulation type (capsule, tablet, tincture) with expected low amounts of ginkgolic acids in the analyzed herbal samples. Separation of ginkgolic acids C15:1 and C17:1 on HPTLC RP18 WF254s was preceded by its separation from the sample matrix on TLC Si60 F254s. Mobile phases consisted of acetonitrile/water/formic acid (80:20:1, V/V/V) and n-heptane/ethyl acetate/formic acid (20:30:1, V/V/V), resp. Identification of separated compounds was based on 2D-TLC co-chromatography with reference substances and off-line 2D-TLC x HPLC-DAD-ESI-MS analysis. Quantification of ginkgolic acids C15:1 and C17:1 was conducted densitometrically. Among the analyzed products, the presence of ginkgolic acids was confirmed only in herbal drugs containing 60 % ethanolic tinctures of Ginkgo biloba leaves. The use of TLC in the quantification of ginkgolic acids C15:1 and C17:1 in ginkgo extracts was described for the first time.