J. Peking Univ. (Beijing Daxue Xuebao) 27, 680-685 (1991). Two-dimensional TLC of amino acids on silica with chloroform - methanol 17% NH3 4:4:2 for the 1st direction and phenol - water 3:1 for the 2nd. Detection by spraying with 0.5% ninhydrin in acetone. Quantification by spectrophotometry at 570 nm after elution.

J. Liquid Chromatogr. 17, 1317-1326 (1994). TLC of 18 amino acids on different layers with 6 solvent systems. Detection by spraying with a solution of 0.3 g ninhydrin in 100 mL butanol plus 3 mL acetic acid and heating at 110 °C for 20 min. Quantification by densitometry at 610 nm. Comparison of the results with those reported earlier using column IEC and reverse-phase HPLC.

J. Chromatogr. A 704, 173-178 (1995). TLC of amino acids on laboratory-prepared zeolite - cellulose 1:1 with water-saturated phenol - ethanol - water - acetic acid 12:4:4:1. Detection by spraying with 1 % ninhydrin solution in i-butanol and heating at 80 °C for 20 min. Determination by visible reflectance spectrometry, image analysis and densitometry. Investigation of the precision, detection limit and limit of quantification for each method.

J. Agric. Food Chem. 46, 277-280 (1998). Detection of Amadori compounds in reaction mixtures (carbohydrates and amino acids) and in stored dehydrated orange juice. TLC of i.a. arginine, proline, fructosyl-y-aminobutyric acid on cellulose with 1-butanol - pyridine - water 2:3:1. Detection by spraying with 0.5% 2,3,5-triphenyl-2H-tetrazolium chloride in 0.5 mol/L sodium hydroxide solution.

J. Planar Chromatogr. 13, 217-220 (2000). TLC of L-lysine, L-threonine, L-homoserine on silica gel with 2-propanol - 25 % NH3 11:9, 1-propanol - acetone - water - 25 % NH3 25:25:7:6 and 2-propanol - ethyl acetate - 25 % NH3- water 40:40:3:50. Visualization by dipping in a 1 % ninhydrin solution in acetone. TLC of vitamin B12 and its derivatives on aluminium oxide with 2-methylpropan-1-ol - 2-propanol - water 3:2:2. - Quantitation by densitometry at 500 (for ninhydrin-amino acid complexes) resp 548 nm (for cobalamines).

J. Liq. Chrom. & Rel. Technol. 26, 2697-2702 (2003). HPTLC of 19 amino acids (alanine, arginine, asparagine, aspartic acid, glycine, glutamic acid, histidine, isoleucine, leucine, lysine, methionine, ornithine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine) on silica gel, cellulose, strong acid cation-exchange sheets, and on RP-18, pre-cleaned by development with dichloromethane - methanol 1:1. Propanol - 0.5 M NaCl 2:3 was used as eluent for the RP phase, pH 3.3 citrate buffer for the ion exchange layer, and n-butanol - acetic acid - water 3:1:1 for the other two layers. Detection by spraying heavily with ninhydrin reagent (0.3 g ninhydrin and 3 mL acetic acid in 100 mL butanol), air drying for 30 min, and heating for 10 min at 110°C on a plate heater. Quantitation by densitometry at 495 nm for histidine and 610 nm for all other amino acids.

J. Liq. Chromatogr. Relat. Technol. 31, 1986-2005 (2008). TLC of L-alpha-phenylalanine on silica gel (prewashed by development with methanol - water 9:1) impregnated by dipping for 2 s in a 24 mMol/L aqueous solution of copper sulfate, followed by drying for 10 min at 110 °C and dipping in 30 mMol/L proline in water - methanol 9:1. The mobile phase was n-butanol - acetonitrile - water 6:2:3. Quantitative determination by absorbance measurement at 200 nm. The ability of L-alpha-phenylalanine to undergo oscillatory transenantiomerization was demonstrated. A skeleton molecular mechanism for the same process was proposed.

J. Planar Chromatogr. 24, 16-22 (2011). A novel method is proposed for optimization of simultaneous thin-layer chromatographic separation of seven amino acids. For this purpose a useful combination of genetic algorithms (GA) with artificial neural networks (ANN) was employed. Methods investigated in this work were successfully used for prediction of resolution (RS) and optimization of the separation of model solutions containing the seven compounds. Very good correlation was achieved between predicted and calculated RS data, and low absolute and relative errors were obtained. TLC of alanine, asparagine, cysteine, leucine, phenylalanine, serine and threonine on cellulose with butanol - acetic acid - water 11:4:5 in a saturated chamber. Detection by spraying with ninhydrin reagent, followed by heating on a plate heater. The hRf values of the amino acids were 30, 36, 44, 50, 52, 72, and 79, respectively.