Direct thin layer chromatography enantioresolution of some basic DL-amino acids using a pharmaceutical industry waste as chiral impregnating reagent.

Direct enantiomeric resolution of DL-arginine, DL-histidine, DL-lysine, DL-valine and DL-leucine into their enantiomers was achieved by thin layer chromatography (TLC) on silica gel plates impregnated with optically pure (1R, 3R, 5R)-2-azabicyclo[3,3,0]octan-3-carbo-xylic acid (0.011 M) as a chiral selector which is a waste of a pharmaceutical industry. Different combinations of acetonitrile-methanol-water were found to be successful in resolving the DL-amino acids. The spots were detected by ninhydrin (0.2% in acetone) and the detection limit was 0.66 microg.

Direct enantioseparation of some beta-adrenergic blocking agents using impregnated thin-layer chromatography.

The resolution of (+/-)-atenolol, (+/-)-propranolol and (+/-)-metoprolol into their enantiomers was achieved by TLC on silica-gel plates impregnated with optically pure L-lysine (0.5%) and L-arginine (0.5%) as the chiral selectors. In all cases, different combinations of acetonitrile-methanol solvent systems were found to be successful in resolving these compounds. Spots were detected using iodine vapour. The detection limit for both (+/-)-atenolol and (+/-)-propranolol was 2.6 microg and for (+/-)-metoprolol, it was 0.26 microg.

Direct enantiomeric resolution of some 2-arylpropionic acids using (-)-brucine-impregnated thin-layer chromatography.

Direct enantioseparation of (+/-)-ibuprofen and (+/-)-flurbiprofen was achieved by two-dimensional thin-layer chromatography on silica gel plates impregnated with optically pure (-)-brucine as chiral selector. The solvent systems that were successful in resolving both the compounds were acetonitrile-methanol (16:3 v/v) for the first dimension and acetonitrile-methanol-water (16:3:0.4, v/v) for the second dimension. Iodine vapour was used for detection; the detection limit for both (+/-)-ibuprofen and (+/-)-flurbiprofen was 0.1 microgram.