Chapter 6 - Thin-Layer Chromatography

Abstract

Thin-layer chromatography (TLC) traces its origins to the introduction of drop chromatography in the late 1930s. A microscope slide is covered with a layer of aluminum oxide, on which one drop of extract is spotted, followed by drop-wise addition of solvent onto this spot. Separated substances are visualized as circular zones radiating from the original spot center. For analytical applications, drop chromatography offers a faster, more convenient, and more powerful separation tool than conventional column chromatography. Devised standardized procedures are used to improve the separation performance and reproducibility of thin-layer chromatography, paving the way for its commercialization, as well as contributing many new applications. The fine particle layers and associated instrumentation were introduced in 1970s for their correct use. In this form, thin-layer chromatography became known as high-performance TLC, instrumental TLC, or modem TLC to distinguish it from its parent, now generally referred to as conventional TLC. Modern TLC did not displace conventional TLC from laboratory studies and the two approaches coexist today because of their complementary features. Conventional thin-layer chromatography provides a quick, inexpensive, flexible, and portable method for monitoring synthetic reactions and similar applications.