Proc. Intern. Symp. on Planar Separations Plan. Chrom. 163-178 (2003). Application of a new concept, the process of flowing eluent wall (FEW), for single and multi-channel on-line overpressured layer chromatography (OPLC) separation with non-segmented sorbent bed for operating segmentation. OPLC of dyes, chamomile oil, ascorbigen, and homogenized cabbage on silica gel with different mixtures of hexane - ethyl acetate, chloroform - methanol - acetic acid 90:10:1. Derivatization with freshly prepared vanillin-sulfuric acid reagent or 10% molybdatophosphoric acid in n-propanol (120°C for 5 min). Detection under UV 254 and 285 nm.

J. Liq. Chromatogr. Relat. Technol. 29, 2045-2057 (2006). TLC of substituted trans-piperidinones comprising 15 amidolactames and 7 aminolactames on silica gel with 13 mobile phase systems with LSChrom software. The procedure takes into account the adsorption properties of the mobile phase (parameter epsilon), stationary phase, and sample structure expressed by the relevant group.

Phosphorus, Sulfur Silicon Relat. Elem. 184, 1139-1148 (2009). The new TLC system for sulfide ions detection is based on the use of 2,4,6-triphenylpyrylium salts as pre-chromatographic derivatization reagents. The cations L1 (2,4,6-triphenylpyrylium) or LN1 (4-[p-(N,N-dimethylamino) phenyl]-2,6-diphenylpyrylium) were used in the derivatization reactions in a tube or directly on the TLC plate before the developing step. TLC of L1 on silica gel with methanol – dichloromethane 1:5. TLC of LN1 on cellulose with phosphoric buffer (pH 6.0) – acetonitrile – 1,4-dioxane 4:2:1. The detection procedure allows selective and sensitive detection for sulfide anions at several dozen pmol/spot.

J. Chromatogr. A, 1572, 145-151 (2018). Introduction of on-surface reactions as a new strategy for rapid structure elucidation. This was illustrated by a miniaturized on-surface synthesis-guided identification of two new degradation products (impurities) occurring in a pharmaceutical formulation of the anti-cancer drug ifosfamide, especially in the presence of urea. The respective reagents were applied in the nanomole scale accurately and automated on a HPTLC silica gel plate. After a fast reaction in the start zone, the plate was developed, followed by online elution to high-resolution MS, whereby the on-surface reaction highlighted the impurities. As proof of concept and for benchmarking, it was compared to a reaction mixture obtained from conventional preparative synthesis in a round-bottom flask as well as to different formulations. Image evaluation was performed by videodensitometry. Discussion of the advantages such as: 1) the combination of all relevant steps on one HPTLC plate and its resulting efficiency made surface synthesis on chromatographic phases an optimal tool for signal highlighting in MS, and thus for the assignment of impurities in drugs; 2) the miniaturization of the chemistry process scale down to the μg-level per synthesis (in total 30-60 μg chemicals/reaction), setting a new state-of-the-art standard; 3) the contribution to a greener chemistry by reducing the consumption of chemicals and enhancing the analytical efficiency, when adapted for the quality control of any other chemical product.

for thin-layer chromatography). TLC of herbal constituents, isopimaric acid, sesamin, paulownin, curolione, curcumo, artemether, emodin, artemisinin, gossypol and gallic acid. Detection by spraying with 1 % vanillin in 60% sulphuric acid. Pharmaceutical research, Chinese herbal medicines.

Part 2. Chromatographic applications. Anal. Chim. Acta 227, 155-163 (1989). TLC of coumarin-6-sulphonyl chloride derivatized amino acids on silica with chloroform – ethyl acetate – methanol – acetic acid 20:20:9:1. Detection by absorbance at 320 nm, or by spraying with ethanol, by fluorescence 366/>500 nm at 77°K. Detection limits in the ng level of analyte for both procedures.

Anal. Biochem. 217, 335-337 (1994). TLC of cyclic peptides on silica with butanol - acetic acid - water 4:1:1. Immersion of the plates in 20% trichloroacetic acid solution for 10 min, and in 0.3% aqueous Serwa Blue W solution for 5 min with gentle shaking. Detection sensitivity, less than 1 µg (0.7 nmol) peptide per spot.

J. Planar Chromatogr. 10, 63-67 (1997). TLC of unsaturated fatty acids (cis-6-, cis-9-, cis-11-, cis-12-, cis-13-, trans-9-, trans-11-octadienoic acid, cis-6,9,12- and cis-9,12,15-octadecatrienoic acid) on silica, silica-kieselguhr and silica impregnated with a 10% solution of paraffin in hexane. Eluents were heptane - acetone 4:1 for adsorption TLC and acetic acid - water 9:1 for partition TLC. Visualization with aqueous solutions (0.5 g/L) of aniline blue, alkaline blue, brilliant green, and neutral red; and in 2% aqueous sodium hydroxide solutions (0.5 g/L) of bromothymol blue, thymol blue, bromophenol blue, phenol red, helasol green, bromocresol green, and brilliant cresyl blue. The most advantageous visualizing effects in adsorption and partition TLC were obtained with aniline blue. Detection limits 2-3 µg of unsaturated fatty acids.