Chromatographic analysis (TLC) of zopiclone and benzodiazepines

The selectivity of the separation of zopiclone and benzodiazepines has been investigated by TLC on silica and alumina with butan-2-one, butan-2-one-to luene, 6 + 4(v/v), toluene-1,4-dioxane-triethylamine, 12 + 7 + 1 (v/v), and cyclohexane-ethyl acetate, 5 + 5 (v/v) as mobile phases. The compounds wer e separated in horizontal chambers and visualized by UV irradiation at lamb da = 254 and 366 nm, and by use of different reagents. The detection limit of zopiclone after visualization with ferric chloride-iodine as reagent was 50 ng; for visualization by UV irradiation at lambda = 366 nm the detectio n limit was 20 ng.