Gas Chromatography & Checking Purity

• • The mobile phase is an un reactive carrier gas
• • The stationary phase is a very thin layer of liquid on an un reactive solid suppourt
• The sample is heated to evaporate it and then passed into the column in the carrier gas
• Substances that have a greater attraction for the mobile phase pass through the mobile phase quickly and have a short retention time
• Substances that have a greater attraction to the stationary phase takes much longer to pass though the column
• Retention time is the time take for each component to travel though the column
• A detector send a signal to a computer as each components leave the column and produces a chromatogram in which each component is peaked plotted a grains travelled time