Consideration of separation mechanisms of some aliphatic and aromatic amines. J. Chromatogr. 609, 419-422 (1992). Investigation of the chromatographic behavior of ten aliphatic and aromatic amines on polyacrylonitrile layer with seven aqueous solvent systems. Discussion of the separation mechanisms.

J. Planar Chromatogr. 7, 480-484 (1994). TLC of amino acids on silica impregnated with a variety of sulfates, oxides, acetates, thiocyanates, chlorides, carbonates, nitrates of transition metals with butanol - water - acetic acid 4:2:2. The systems reported were considered as improvements with regard to the number of amino acids resolved from a complex mixture and can be used successfully for the analysis of unknown mixtures. Detection by spraying with ninhydrin solution and heating at 80-100 °C for 5-10 min.

J. Planar Chromatogr. 11, 84-89 (1998). Improvement of the DRIFT (diffuse reflectance infrared Fourier spectroscopy) spectra and increase of the signal-to-noise ratio by application of a combination of silica gel 60 and a weak infrared-active, reflection-enhancing material. Of the reflection-enhancers tested magnesium tungstate proved to be the most suitable; the optimum proportion was 50%. For this type of layer the signal-to-noise ratios for caffeine, paracetamol, and phenazone were increased by factors of 3.4, 3.1, and 2.3, respectively, compared with those obtained on pure silica gel 60. Use of material of small mean particle-diameter and narrow particle-size distribution provided an almost optimum diffuse reflecting surface.

J. Planar Chromatogr. 14, 234-236 (2001). In contrast to 'traditional' layers used in TLC and HPTLC, the new sorbent is no longer based on granular material, but consists of monolithic layers with a defined pore structure based on a silica gel matrix. Furthermore, no binder is needed to fix the layer on the plate. The layer thickness of approx. 10 µm is considerably less than that of conventional layers. The exciting properties of the new UTLC silica gel plates, especially their selectivity and separation efficiency, reduction of analysis time and solvent consumption, is demonstrated by separations of steroids, pesticides, and some dyes.

Proc. Intern. Symp. on Planar Separations Plan. Chrom. 71-74 (2003). Ultra-thin layers exhibit a thickness of 10 mm and consist of monolithic silica eliminating the need for a binder to fix the layer on the glass surface of a plate resulting in the combination of short migration distances, fast development times, and extremely low eluent consumption. LuxPlate, a new TLC plate, is characterized by a higher amount of fluorescent indicator and are twice as bright under UV light when compared to conventional TLC plates.

GIT Suppl. Chromatogr. 3, 32-38 (1986); part II: GIT Fachz. Lab. 10, 993-998, (1986). Principle and applicability of TLC using mobile phase pressure of up to 80 bars. Circular development of single sample injected in-flow and of multi samples applied on the dry layer. Use of normal and reversed phase material, including multiple use of the same layer. Quantification of the chromatograms by direct image processing using optical sensitive RAM.

J. Planar Chromatogr. 13, 470-472 (2000). Evaluation of the application of new materials (both chromatography and filter paper) as the concentrating zone; evaluation of the possibility of combining paper and TLC on a flexible support; and realization of a simple variant of the technique (paper and TLC plate) which would enable realization of the technique in any laboratory. TLC of methyl orange, methyl red and methyl green (0.1% in ethanol) with ethanol as mobile phase on silica gel with concentrating zone and Sorbfil polymer resp. on silica gel with chromatography paper instead of the concentrating zone.

Anal. Chem. 76, 1690-1695 (2004). Pressurized planar electrochromatography (PPEC) is a new planar chromatographic technique in which the mobile phase is driven by electroosmotic flow, while the sorbent layer is pressurized in a manner that allows heat to flow from the layer through an electrically insulating, thermally conducting sheet of aluminum nitride ceramic. Separation in a PPEC prototype apparatus is faster than by conventional TLC, and an example is presented of a 24-fold enhancement in the speed of separation. PPEC was performed on TLC and HPTLC RP-18 phases which required conditioning at elevated temperature before use. Solute migration velocity increases with temperature. The flow rate increases in a linear manner with increasing voltage and diminishes in a nonlinear manner with increasing pressure. Both electrical current and Joule heating diminish with increasing pressure, and the diminution of flow at high pressure can be compensated by an increase in voltage. PPEC is more efficient than classical TLC. Theoretical plate heights diminish with increasing hRf and are in the range 29-21 and 55-27 µm for the HPTLC and TLC, respectively. PPEC retains the advantages of classical TLC, but has the ability to separate a substantially higher number of samples. An example is presented on the separation of nine samples in 1 min.