8. Integration problems in QTLC. J. Planar Chromatogr. 2, 128-132 (1989). Some integration problems in quantitative TLC are illustrated. A prepared program simulates chromatograms with different position, concentrations, and shapes of chromatographic peaks. The results of integration are presented and discussed. In TLC it is necessary to find the correct peak start. Evaluation of a small peak after a big one can be done more precisely than the evaluation of a small one in front of a large one.

J. Planar Chromatogr. 28, 126-132 (2015). TLC of 17 morphine derivatives on RP phase with 3 different mobile phases, (1) methanol - 0.02 M ammonium hydroxide, (2) methanol - 0.7 M ammonium hydroxide, and (3) methanol - 0.02 M acetic acid. In each case, the individual mobile phases contained 30-90 % (v/v; in 10 % increments) of methanol as an organic modifier. Detection by absorbance measurement at 254 nm. RP-TLC can be used for the characterization of the lipophilicity of semisynthetic derivatives of morphine.

J. Chromatogr. 500, 661-671 (1990). Development of a system making color reactions on TLC plates amenable to computer handling. Identification of unknown substances using corrected Rf values and color reactions by means of computerized retrieval from large data base, based on a series of four color reactions carried out in sequence on the same spot and by numeric encoding of the observed color with a color reference chart. Comparison of the identification power with that of GC. GC retention indices and UV absorption maxima can also be introduced in the identification program. Use of a single TLC system with color reactions provides about the same identification power as a single GC system and can be increased by using two or more different TLC systems in parallel.

J. Planar Chromatogr. 28, 115-118 (2015). TLC of 35 compounds on RP-18 and cyano phase with six modifiers (acetonitrile, acetone, dioxane, propan-2-ol, methanol, and tetrahydrofurane). The extrapolated Rm data were recomputed and compared to HPLC results with 2 modifiers. HPLC (in gradient mode) and TLC perform in comparable manner in the lipophilicity assessment of the investigated model compounds. With its simplicity, it is a strong argument to use TLC in lipophilicity studies.

Proc. 6th Int. Symp. Instrum. Planar Chromatogr., (Interlaken 1991), Inst. Chromatogr., Bad Dürkheim, FRG, 273-282 (1991). Densitometry by slit scanning mode was compared with processing mode using a video camera. A sugar TLC-chromatogram was used as example; chromatographic data not stated.

J. Planar Chromatogr. 29, 299-305 (2016). Analysis of the antioxidants ascorbic acid (1), gallic acid (2), caffeic acid (3), quercetin (4), and biogenic amines (–)-epinephrine (5), (–)-norepinephrine (6), isoprenaline hydrochloride (7), dopamine hydrochloride (8), 3,4-dihydroxy-d-phenyl-alanine (d-dopa) (9), and 3′,4′-dihydroxy-2-(methylamino)acetophenone hydrochloride (adrenalone) (10) applied as individual zones in different concentrations on silica gel, without development. Radical-scavenging activity was measured by spraying with 0.03 % 2,2-diphenyl-1-picrylhydrazyl (DPPH radical reagent) solution in methanol and stored in dark at 22 °C for 5 min, followed by scanning in a dark place. Image data was converted into chromatograms, from which the spot area as a function of the reaction time was monitored. The title "Chromatographic approach" is misleading, as there is no chromatography.

J. Chromatogr. 553, 477-487 (1991). Description of a computer program which enables scanning and evaluation with a TLC scanner. Use of the method in quantitative determination of some phenolic components in propolis, and identification and quantification of some typical flavonoids.

J. Planar Chromatogr. 29, 310-317 (2016). HPTLC fingerprinting of two types of German propolis on silica gel with n-hexane – ethyl acetate – glacial acetic acid 5:3:1 under acidic preconditioning. Detection and documentation under UV 366 nm. Image analysis by converting chromatogram images to numerical data sets to form a data matrix. The best preprocessing was obtained by a combination of the median filter, correlation optimized warping, standard normal variate, and mean centering/autoscaling procedure.