J. Planar Chromatogr. 8, 117-121 (1995). HPTLC of monosodium glutamate on silica (no indication of the mobile phase), threefold ascending development to a height of 60 mm, in an unsaturated tank. Detection by spraying with ninhydrin solution. Quantification by densitometry at 520 nm (absorbance). Detection limit 3 mg MSG/mL. Compared with the enzymatic method, TLC is quick, precise, cheap, and suitable both for industrial quality control as well as for occasional analyses.

Anal. Chim. Acta 316, 105-110 (1995). Study of the interaction of 23 antisense nucleosides with amino acids by charge-transfer reversed-phase TLC, and evaluation of the retention matrix by principal component analysis. Discussion of the effect of amino acids on the retention of nucleosides, and stacking interactions between the ring structures of nucleosides and Trp and Phe.

J. Planar Chromatogr. 11, 300-304 (1998). Determination of the TLC retention of fifteen amino acids on silica gel layers developed with different mobile phases. Visualization with ninhydrin solution. Correlation analysis was conducted and fifteen parameters are discussed - including topological indexes and physicochemical properties - three of which were selected with both topological and physicochemical significance for construction of multi-parameter regression equations for prediction of the Rf values of the amino acids. Experimental results were in good agreement with calculated values, which confirms the accuracy of the predictions. - TLC of 15 amino acids on silica gel with ethanol - water 4:1, 8:1, 2:1 and propanol - acetic acid - water 3:1:1, 6:2:1, 1:1:1. Densitometry at 460 nm after visualization and heating for 1.5 - 2 min at 105°C.

J. Chromatogr. A 888 (1/2), 335-339 (2000). Investigation of the TLC behavior of the natural, sulfur-containing amino acids (Cys, Hcys, Met) and their phosphonic analogues (Cysp, Hcysp, Metp) by employing 8 TLC systems. Determination of the detection limits of the compounds using iodine and molybdate, ninhydrin and iodine-azide reagent. Comparison of the Rf values of the two classes of amino acids in acidic, neutral and mild basic solvent systems.

J. Planar Chromatogr. 17, 113-122 (2004). HPTLC of serine, threonine, phenylalanine, tryptophan, lysine, ornithine, arginine, valine, and leucine on silica gel with A) 2-propanol - ethyl acetate - 25 % ammonia - water 40:40:3:50; B) 2-propanol - acetone - water - 25 % ammonia 25:25:7:6; C) 2-propanol - 25 % ammonia 7:3; D) chloroform - 96 % ethanol - acetic acid - water (52.5-54.0):(26.0-27.5):(8.9-9.6):(3.5-4.2); E) 1-propanol - 25 % ammonia 11:9; F) 1-propanol - 25 % ammonia - water (3.3-4.1):(0.9-1.5):(7.5-9.0); G) t-amyl alcohol - 2-butanone - water 22:6:5, upper layer, in a presaturated twin-trough chamber. Detection by dipping into a ninhydrin solution. Quantitative determination by reflectance measurement at 500 nm.

J. Liq. Chromatogr. Relat. Technol. 31, 752-762 (2008). TLC and HPTLC of nine dipeptides (gly-gly, ala-gly, pro-leu, pro-asp, pro-gly, leu-pro, ala-pro, phe-pro, val-pro) on silica gel with ethanol - dichloromethane 2:1 and methanol - dichloromethane 1:1 in a horizontal chamber saturated for 20 min. Detection by spraying with sodium azide and starch solution (25 mL aqueous starch solution, containing 2.5 g starch, was added to 20 mL aqueous sodium azide solution containing 2 g sodium azide, the mixture was adjusted to pH 5.5 with 0.1 mol/L hydrochloric acid and diluted to 50 mL with water to obtain 4 % and 5 % solution for sodium azide and starch, respectively). All solutions were prepared fresh daily. The limit of detection was 2-200 pmol/spot for the iodine azide procedure, 1-100 pmol/spot for iodine, 20-2000 pmol/spot for UV 254 nm, and 40-1000 pmol/spot for spraying with ninhydrine and drying at 110 °C .

Anal. Chem. 324, 339-340 (1986). TLC of dipeptides on a) microcrystalline cellulose with pyridine - water 2:1 and 4:1 and b) on chiral plate with methanol - water - acetonitrile 5:5:20 and 5:5:3. Detection with ninhydrin reagent.

J. Chromatogr. 448, 11-30 (1988). TLC of proteinogenic and non-proteinogenic amino acids, dipeptides and a-hydroxy acids. Separation of the enantiomers, without derivatization, on a chiralplate. Quantification by densitometry. Determination of the respective enantiomers at trace levels (0,25%). Detection limits: 0.1% of the minor enantiomer. Other examples from the field of +-methyl, N-alkyl and halogenated amino acids.