Biochemical Techniques and Instrumentation

2.6.7. Preparative TLC

Preparative TLC is used on semi-preparative scale to separate compounds upto a few hundred milligram. In this technique, the sample mixture is not "spotted" on the TLC plate as dots, but is applied as a thin even layer horizontally to and just above the solvent level as a band. The compounds separate as horizontal bands rather than as spots upon development with the solvent. Each band is then scraped off, extracted with a suitable solvent and filtered to get the preferred compound upon removal of the solvent. Preparative TLC is far more efficient in terms of time and cost than column chromatography. This technique is best used for compounds that are coloured or visible under UV light.