Wmctc chromatography Workshop: 7th Feb 2017 Ian J. Shannon

• WMCTC Chromatography Workshop: 7th Feb 2017

• Ian J. Shannon
• School of Chemistry

Objectives

• General Concepts/ & Terminology
• Practical aspects of TLC
• dips, artefacts, additives
• columns
• Advanced techniques
• GC
• HPLC

Concepts & Terminology

• Uses
• Analysis and Purification
• Separation of Components
• Stationary Phase
• Usually Silica/Alumina
• Mobile Phase
• Solvent, referred to as “Eluent”

• TLC – Silica

• Silica supported on plate (Aluminium Foil)

• Solvent Molecule
• (Mobile Phase)

• Hydroxyl-terminated Silica
• (Stationary Phase)

• Al Foil
• (Backing Plate)

• TLC – Paper Chromatography

• Water molecules on Surface of Paper/Cellulose

• Solvent (Mobile Phase) moves across surface through capillary action

• Water molecules hydrogen-bond to surface to form Stationary Phase)

• Paper/Cellulose
• (“Backing Plate”)

TLC Uses

• Used for analysing mixtures
• Monitoring reactions
• Analysing column chromatography fractions
• e.g. separating menthol
• and limonene

• Preparation of a TLC Plate

• Analysing a Reaction

• A + B -> Products

• Running a TLC Plate

• What is Happening?

• Completion of TLC

• Don’t forget to mark the solvent front with a pencil at the end!

Visualisation

• UV – commonly 254 nm
• Dips – not all spots are visible under UV
• Iodine
• KMnO4 solution
• Vanillin solution
• Ninhydrin
• FeCl3 solution
• Ceric Ammonium Molybdate (CAM)
• Sulfuric Acid