Biomed. Chromatogr. 10, 37-39 (1996). TLC on Cu(II)-impregnated silica with butanol - acetate buffer (0.3 M pH 6.0) - acetonitrile 10:12:5. Detection by spraying with 0.2 % ninhydrin in acetone and heating at 60°C for 30 min. Comparison of the results with those obtained by HPLC.

J. Planar Chromatogr. 11, 346-349 (1998). TLC of the enantiomers of several unusual aromatic amino acids (phenylalanine, tyrosine, histidine, and tryptophan analogs, and analogs containing tetralin or 1,2,3,4-tetrahydroisoquinoline skeletons) synthesized in racemic or homochiral form on chiral plate with acetonitrile - methanol - water 4:1:1; 4:1:2 or acetonitrile - methanol - water - diisopropylethylamine 40:10:20: 1. Visualization with ninhydrin.

Proc. Intern. Symp. on Planar Separations, Planar Chromatography 2001, pp. 355-362. TLC of lysine, threonine, homoserine, tryptophan, and phenylalanine on silica gel with 1-propanol - 25% NH3 11:9, 2-propanol - acetone - water - 25% NH3 25:25:7:6, 2-propanol - ethyl acetate - 25% NH3 - water 40:40:3:50 and 2-propanol - 25% NH3 7:3. Detection of tryptophan by immersion for 40 s in a 0.5% solution of 4-dimethylamino-benzaldehyde in ethanol containing 5% conc. sulfuric acid and heating at 110°C for 5-7 min. Amino acid spots were scanned with two different densitometers.

J. Planar Chromatogr. 18, 251-252 (2005). TLC of 22 silylated amino acids on silica gel with butanol. After spotting the plates with the amino acid solutions the samples were sprayed with hexamethyldisilazane reagent (1 % solution in acetone), dried, heated at 110 °C for 20 min, and cooled. The developed plates were dried, sprayed with ninhydrin (0.25 % solution in acetone), dried completely, then further heated at 110 °C for 20 min. Detection limits of this method within 10 min are comparable with those of other methods.

J. Planar Chromatogr. 22, 65-71 (2009). Presentation of two simple and rapid HPTLC methods for early detection of the effects of herbicides using two different groups of plant biomarkers, which were developed as field tests (Herbicide Weed Response test - HWR-Test). Phytochemical changes can be detected before any morphological changes are visible on the plants. These changes are defined as biomarkers and can be detected by HPTLC-screening. After overall identification of the phytochemical biomarker pattern, two different biomarker groups, carbohydrates and amino acids, were detected using modified reagents for color reactions. Evaluation under daylight and videodensitometric analysis of digital images by VideoScan software. The screening method was previously described [H. W. Ravn, M. Hjorth, L. Lauridsen, P. Kudsk, S. K. Mathiassen, L. Mondolot, Bull. Environ. Contam. Toxicol. 75, 236-245 (2005)].

J. Planar Chromatogr. 26, 180-189 (2013). HPTLC of 2,4-dinitrophenyl-5-L-valine amide derivatives of some amino acids (leucine, isoleucine, valine, asparagine, cysteine, tryptophane) L and D-enantiomers on RP-18 with aqueous buffer pH 2.2 (1.47 mM citric acid, 0.06 mM disodium hydrogen phosphate) and acetonitrile 50 %. The statistic evaluation of the migration distance compared with pressurized planar electrochromatography (PPEC) shows similar RSD.

J. Ethnopharmacol. 202, 97-102 (2017). HPTLC of betaine in the roots of Achyranthes aspera on silica gel with methanol – water 9:1. Detection by spraying with Dragendorff's reagent, followed by 10 % ethanolic sulfuric acid and drying at 110 °C for 5 min. Quantitative determination by densitometry at 520 nm. The hRF value for betaine was 36. Linearity was between 1 and 5 μg/band. The intermediate precision was below 2 % (n=6). LOD and LOQ were 0.13 μg/mL and 0.10 μg/mL, respectively. (Note: The reported LOD and LOQ do not make sense, as LOD is higher than LOQ.)

II. Problems in the choice of the solvent system. Proc. Intern. Symposium on TLC with special Emphasis on OPLC, Szeged, 94-95 (1984). OPLC (OPTLC) of beta-amino-isobutyric acid on silica with chloroform - butanol- DMF - acetic acid 91:2:2:1. Detection with ninhydrin reagent. Densitometry. Separation of urine constituents for the purpose of determining beta-amino-isobutyric acid (a possible tumor maker).