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. Liq. Chromatogr. Relat. Technol. 28, 2619-2632 (2005). TLC of homopeptides of alanine, glycine, lysine, and phenylalanine on alumina (impregnated by overnight development in n-hexane - paraffin oil 19:1) with water and 0.05 M aqueous solution of LiCl, NaCl, RbCl, and CsCl, containing different amounts of HP-beta-CD. Development in sandwich chambers, followed by drying at 100 °C. Detection by spraying with ninhydrin reagent (0.3 g ninhydrin in 100 mL n-butanol containing 3 mL acetic acid). In order to increase the sensitivity of detection, the plates were sprayed with 2 M aqueous acetic acid prior to the ninhydrin reaction.

Biochem. Biophys. Res. Commun. 394, 448-452 (2010). HPTLC of [14C]-L-arginine and [14C]-L-citrulline of a nitric oxide synthase conversion assay in mitochondria rat liver, on silica gel with butanol - acetic acid - water 3:1:1. Detection by dipping in a solution of 2 % ninhydrin in acetone, followed by heating on a plate heater for 1 min. After visualization, the plates were exposed to X-ray film for 4.5 days.

J. Planar Chromatogr. 26, 517-520 (2013). TLC of amino acids on silica gel with 1-propanol - water 7:3. Detection by spraying with (1) 1 % 2-hydroxybenzenecarbaldehyde solution in propanone; or (2) 1 % 4-bromobenzenecarbaldehyde solution in propanone (2), followed by heating at 110 ºC for 10 min. After cooling, all plates (treated with (1) or (2)) were sprayed with ninhydrin (indane-1,2,3-trione monohydrate) reagent and air dried. Amino acid zones in various shades from yellow to brownish-red were detected (detailed table provided in paper). Plates were heated again at 110°C for 10 min and color changes were recorded. The LOD were determined visually by comparison of standard solutions (1 mg/L) and further dilution until no zone was seen. LOD for (1) and (2) were in the range of 0.1-1.0 µg/zone and 0.01-1.0 µg/zone, respectively.

J. Liq. Chromatogr. Relat. Technol. 41, 373-376 (2018). HPTLC of 22 amino acids in the cultures of control and starved Biomphalaria glabrata snails on cellulose plates with 2-butanol – pyridine – acetic acid – water 39:34:10:26. Detection by spraying with 2 % ninhydrin solution in n-butanol – acetone 1:1, followed by heating at 110 ºC for 10 min. Quantitative determination by absorbance measurement at 610 nm. Samples were also analyzed on RP-18 with water – methanol 3:7 with addition of 100 mM formic acid in the bonded phase normal phase mode and water – methanol 7:3 with the addition of 100 mM trifluoroacetic acid in the bonded phase reversed phase mode. Although better separation results were obtained with the cellulose plates, an excellent separation of the pair Ile and Leu with the RP-18 W was noted.

Chromatography the State of the Art, Vol. II. Akademiai Kiado, Budapest 1985, 591-599. OPTLC on silica and HPTLC chromatoplates with different solvent systems. Modified ninhydrin staining reaction.

(Thin-layer chromatographic enantiomeric resolution via ligand exchange.) GIT-Suppl. 3, 6-12 (1986). Separation of enantiomeric amino acids and dipeptides on reversed phase silica gel covered with a chiral selector (proline derivative). Typical developing solvents: methanol - water - acetonitrile 5:5:20 (running time 30 min) and 5:5:3 (running time 90 min).

Talanta 34, 438-440 (1987). TLC of 18 amino acids on silica with water - n-butanol - acetic acid 5:4:1. Detection by spraying with 0.1 % 9-iso-thiocyanatoacridine in dichloromethane or benzene, heating and examining under UV at 254 and 366 nm. Detection limit 100 ng. Details on preparation of the reagent.