Skip to Content
Merck

Thin Layer Chromatography

Silica gel TLC plates showing clearly separated colored spots

Thin layer chromatography (TLC) is an affinity-based method used to separate compounds in a mixture. TLC is a highly versatile separation method that is widely used for both qualitative and quantitative sample analysis. TLC can be used to analyze virtually any substance class, including pesticides, steroids, alkaloids, lipids, nucleotides, glycosides, carbohydrates, and fatty acids.  



Featured Categories

Thin Layer Chromatography (TLC)
TLC Plates & Adsorbants

Choose from classical TLC plates with silica, aluminum, glass, and plastic backings as well as HPTLC plates, MS-Grade TLC and HPTLC plates, and PLC plates.

Shop Products
Various HPLC and UHPLC products
HPLC Columns

Achieve precise separations with our extensive HPLC column collection. Enhance retention, resolution, and selectivity. Order today.
 

Shop Products
ReagentPlus solvent grade products
Solvents

Your Solvent Source: Find the right fit with Supelco®, SigmaAldrich®, & SAFC® brands, covering analytical, lab, & biopharmaceutical uses. Order online.
 

Shop Products
Glass and plastic bottle of acids
Acids

Uncover a wide acid range: Supelco® for analysis, Sigma-Aldrich® for labs, SAFC® for biopharma. Tailor solutions for varied needs.
 

Shop Products

In TLC, the stationary phase is a thin adsorbent material layer, usually silica gel or aluminum oxide, coated onto an inert plate surface, typically glass, plastic, or aluminum. The sample is spotted onto one end of the TLC plate and placed vertically into a closed chamber with an organic solvent (mobile phase). The mobile phase travels up the plate by capillary forces and sample components migrate varying distances based on their differential affinities for the stationary and mobile phases. When the solvent reaches the top of the plate, the plate is removed from the developing chamber and dried. The separated components appear as spots on the plate and the retention factor (Rf) of each component is assessed.

TLC Process and Principles

TLC is based on the classic chromatography principle where mixture components are separated between a fixed stationary phase and a liquid mobile phase by differential affinities between the two phases. 

TLC Retention Factor (Rf)

The retention factor (Rf) is used to measure the movement of compounds along the TLC plate. Rf is defined as the distance travelled by an individual component divided by the total distance travelled by the solvent. Its value is always between zero and one.

R distance traveled by component
distance traveled by solvent


In general, the stronger a compound binds to the stationary phase adsorbent, the slower it migrates up the TLC plate. As TLC adsorbents are typically polar, non-polar compounds tend to travel more rapidly up the plate, resulting in a higher Rf values, whereas polar compounds tend to move slowly and have lower Rf values.

Applications of TLC

TLC is widely used by many industries and research fields, including pharmaceuticals, clinical testing, environmental toxicology, food, water and pesticide analysis, and cosmetics. Typical applications of TLC include:

  • Analysis of drug residues and antibiotics in food and environmental samples
  • Identification and quantification of colors, ingredients, preservatives, and sweetening agents in food and cosmetic products
  • Quality control and purity testing of pharmaceutical formulations
  • Rapid, high-throughput screening prior to HPLC
  • Examination of chemical reactions for completion
Document Search
Looking for More Specific Information?

Visit our document search for data sheets, certificates and technical documentation.

Find Documents

    Sign In To Continue

    To continue reading please sign in or create an account.

    Don't Have An Account?