Anal. Chim. Acta 223, 411-418 (1989). Optimization of multicomponent mobile phase system in TLC by using an overall figure of merit (FOM) for separation, based on an equation which defines the extent of the separation of pairs of spots. Demonstration of the method in simplex optimization of separation of 17 amino acids by two-dimensional TLC on cellulose with tert butanol – 25% NH3 – MEK – water 12:6:1.52:2.48 for the first dimension, and butanol – acetone – acetic acid – water 10.29:6.82:5.06:3.65 for the second.

J. Planar Chromatogr. 3, 65-67 (1990). Description of a method for chromatographic separation of enantiomers involving chiral mobile phase additives. Amino acid derivatives and several alkaloids are separated by TLC on different types of RP plates using a mobile phase containing maltosyl-ß-cyclodextrin. Visualization under 254 nm UV. A comparison was made between octadecyl, diphenyl, and ethyl RP TLC plates.

J. Planar Chromatogr. 6, 294-295 (1993). HPTLC of dansyl amino acids (L-arginine, glutamic acid, glycine, L-leucine, serine) on silica with 5% EDTA - 1-butanol - ether 1:2:7 (2 developments). Quantification by densitometry in fluorescence at 366/>400 nm.

J. Chromatogr. 685, 360-364 (1994). TLC of amino acid racemates on the title plates with 1) 2-propanol - water 7:3, 2) phenol - water 4:1, 3) butanol - acetic acid - water 3:1:1. Detection by spraying with 0.1% ethanolic ninhydrin solution and heating for 5 minutes at 90 °C. Discussion of the enantiomeric separation mechanism.

J. Planar Chromatogr. 9, 375-378 (1996). TLC separation of lysine, homoserine, threonine, and tryptophan from accompanying amino acids in culture liquids on silica gel using 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 after drying for 15 min and heating at 120°C for 15 min, dipping into a solution of 0.5% 4-DMABA in ethanol containing 5% conc. sulfuric acid, and heating for 5-7 min at 110°C. Quantification by densitometry.

of Crop Sci., Univ. of Illinois at Urbana-Champaign, 240 Edward R. Madigan Lab., 1201 West Gregory Drive, Urbana, IL 61801, USA): Detecting and characterizing N-acyl-homoserine lactone signal molecules by thin-layer chromatography. Proc. Natr. Acad. Sci. USA 94, 6036-6041 (1997). TLC of N-acylated derivatives of L-homoserine lactone (acyl-HSLs) on RP-18 with methanol - water 3:2. The spots were visualized by overlay of a bacterial reporter strain. Spots of preparative TLC were scraped off and submitted to Electrospray ionization mass spectrometry (ESIMS).

J. Planar Chromatogr. 14, 462-463 (2001). TLC of 22 amino acids on silica gel with n-propanol - water 7:3. Detection by spraying with a modified ninhydrin reagent resulting in a variety of distinguishable colors with most amino acids, and with high sensitivity: Visualization by spraying with 1% 4-hydroxybenzaldehyde in acetone (reagent 1) and after drying, heating at 110°C for 10 min, cooling, spraying with 0.25% ninhydrin in acetone (reagent 2).

J. Planar Chromatogr. 19, 252-254 (2006). TLC of 22 amino acids on silica gel with n-propanol - water 7:3. Detection by spraying with 0.25 % 2,3-dichloro-1,4-naphthoquinone in ethanol, followed by drying in the air at room temperature and heating in an oven at 110 °C for 10 min. After cooling spraying with 0.4 % isatin in ethanol. Visual detection of spot colors (varying from yellow, to orange, pink, purple, and gray). Detection limits were determined visually and ranged from 0.01 µg (cystine and arginine) to 0.30 µg (isoleucine, phenylalanine, methionine, aspartic acid, and glycine).