NOTES: Two-Dimensional Thin-Layer Chromatography for Amino Acid Analysis of Bacterial Cell Walls

Good separation of bacterial cell wall amino acids, including the isomers of diaminopimelic acid, was obtained by two-dimensional thin-layer chromatography, using commercial cellulose-coated aluminum sheets with isopropanol-acetic acid-water (75:10:15, vol/vol) and methanol-pyridine-10 N hydrochloric acid-water (64:8:2:14, vol/vol) as the first and second solvents, respectively.