3. Linearity

4. OPLC/TLC The linear migration of the eluent front makes OPLC an efficient technique and permits use in semi preparative, it is possible to obtain pure fraction by direct elution, which is not the case in TLC in Oplc the migration is not limited by the dimension of the plate, the flux can be forced and the migration is considerably quicker than TLC, and there is less spot diffusion.

5. OPLC/TLC Si 15 cm en 5 minutes 30 cm en 10 minutes Rendement sans comparaison avec le fastidieux grattage des taches

6. OPLC HPLC En dehors de la semipréparative il convient de noter que l on travaille à front perdu et que l on peut imaginer faire la chromatographie sur 1 m ou 2 A l usage en mode semipréparatif il est nécessaire de décoller vers un rf convenable pour éluer d’une façon linéaire

7. Linearity

8. OPLC 50

9. Objective of the present work Study plant extracts belonging to different chemical classes of secondary metabolism by OPLC Analyze crude plant extracts versus reference substances Apply OPLC to preparative on-line mode

10. Why using planar chromatographic techniques in the analysis of drugs? Short analysis time Low cost Semi quantitative information Drug fingerprinting Detection of adulterations and substitutions Analysis of crude extracts without sample prep Numerous analyses of the same plate

11. Applications in plant drugs analysis Alkaloids and –quaternary ammonium salts Cannabinoids Essential oils Polyphenols: –coumarins –flavonoids –anthocyans

12. Alkaloids Complete separation with OPLC of crude extracts of the most important classes of alkaloids, obtained with only ethyl acetate as the mobile phase on aluminium oxide in total 80 natural and synthetic alkaloids were studied