V. Danube Symposium on Chromatograph, Yalta, November 11.-16. 1986. Two-dimensional TLC of lipids on ammonium sulfate impregnated silica with benzene - dioxane 94:6 and CCl4 ; densitometry. Comparison with enzymatic methods.

Detection by immersing in 40 % sulfuric acid and heating at 110 °C. Quantification by densitometry at 590 nm. Detection limit 50 ng.

Quantitative determination of TLC-separated enantiomers. GIT Suppl. Chromatographie 3, 27-32 (1987). By means of nine examples (D-Phe, tert.-leu, 5, 5-dimethyl-thiazolidine-4-carboxylic acid, O-Bzl-Ser, L-4-iodophenylalanine, L-he, L-tyr, L-methyldopa, D-leu-L-leu) is demonstrated, that the quantitative determination of TLC-separated antipodes is a useful method for daily routine process in any laboratory. The resolution of the enantiomers is excellent, the respective antipodes could be evaluated at trace levels, the limit of determination is found to be at or above 0.1 %. In comparison to the "classical methods" GC and HPLC, TLC offers separation in parallel runs.

(TLC identification of talinolol (Cordanum (R)) in urine, a screening method for monitoring administration of this anticonvulsant.) Pharmazie 42, 165-166 (1987). TLC of talinolol on silica with ethyl acetate - methanol - NH3 80:10:10. Detection under UV 335 nm.

Acta Pharmaceutica Hungarica 58, 247-265 (1988). Study of the determination of hydrophobic constants by TLC. N-Heterocyclic substances were used as model mixtures.

Anal. Biochem. 173, 10-17 (1988). HPTLC on silica with acetone - 5N NH3 50:0.9. Detection by autoradiography. Liquid scintillation, spectrometry after scraping. Fixation of the silica gel and treatment with neuraminidase from Vibrio cholerea in the absence of detergent and incubation of the plates with antibodies. Visualization of bound first antbodies by using alkaline phosphatase conjugated second antibodies. Detection limit, 30 ng.

J. Planar Chromatogr. 2, 65-70 (1989). For qualitative analysis monodansyl cadaverine (MDC) was employed without further purification. Column-chromatographic purification is recommended for the quantification of short chain carboxylic acids. For in situ derivatization the carboxylic acid sample solutions were applied to the HPTLC plates as bands with a maximum length of 10 mm. These were then „overlayed“ with MDC solution containing N,N’-dicyclohexylcarbodiimide to activate the acids. Short-chain carboxylic acids were separated on normal silicagel phases with toluene - ethyl acetate - ammonia mixtures as mobile phase. Stepwise and gradient developments allow the baseline separation. Long-chain carboxylic acids are better separated on RP-18 phases with acetonitrile-tetrahydrofuran mixtures and methanol as mobile phase.

Anal. Chim. Acta 227, 203-209 (1989). HPTLC of reduced glutathione on silica with diisopropyl ether – methanol – water – acetic acid 9:8:2:1 after treatment with trichloroacetic acid and derivatization with ammonium 7-fluorobenzo-2-oxa-1,3-diazole- 4-sulphonate. Detection under UV at 365 nm. Detection limit, in the low nanogram per spot range.