2Basic DescriptionChromatography is a method for separating the components of a mixture by differential adsorption between a stationary phase and a mobile (moving) phase
3Uses for Chromatography Chromatography can be used to:Qualitatively analyze the number of components in a mixtureQualitatively identify the components of a mixture using known compoundsQuantitatively determine the amount of a component in a mixture using standard samplesPurify individual components by separating them from the other compounds in a mixture
4The Basics Mixture is placed on stationary phase Mobile phase passes over the stationary phaseMobile phase carries the individual components through the stationary phase, depending on their attraction to both of the phases
5Rf ratio of spot distance to solvent front distance ChromatographedSpotRf ratio of spot distance to solvent front distancePut the spotted paper in a developing tankOrigin lineSolvent
6Other Kinds of Chromatography Liquid chromatography (includes column chromatography, thin-layer, and HPLC)Stationary phase: silica, alumina, modified surfaces, etc.Mobile phase (moving phase): aqueous or organic solventsImportant properties: polarity, charge, etc.Gas chromatographyStationary phase: a film of a polymer or a wax. The film must have a low volatilityMobile phase: gas (Helium is a common carrier gas)Important properties: boiling point, volatility, etc.
10This Week’s Lab Forensic in nature Start with FTIR to decide what compound class your “unknown” belongs to.Run authentic compounds in that classSeparation is based predominantly on boiling point rather than differential interaction with stationary phaseRun the “unknown” to determine individual identities
11Logger Pro UpdateYou need the latest Logger Pro Update to operate the gas chromatograph from your laptop computer. Go to Select Downloads Select Logger Pro Update Install Correct version for your OS
12Writing the ReportClearly state your experimental methods and how those procedures yielded the solution to the problems addressed in the investigation.State what data you collected and how you analyzed the data.Include properly designed and illustrative data tables.Show structures of all possible compounds in your compound class.Discuss other places that GC might be used beyond this investigation and those described in the Introduction.