Chromatography Flashcards
Chromatography?
Separation technique that relies on a components affinity to either the mobile phase or the stationary phase.
Affinity?
Degree to which a substance tends to combine with another.
Chromatogram?
What you view reaction on (stationary and mobile phase).
Steps of gas chromatography?
- Sample is injected as liquid form into collumn.
- Heat of the oven converts sample into gas state.
- Carrier gas pushes sample through the collumn.
- Those components that bond strongly to the particles in the stationary phase take a longer time to reach the end of the collumn than those components which do not bond strongly.
- Each time a component reaches the detector at the end of the collumn, a signal is sent to the computer.
- The computer produces a chromatogram whoch shows each component as a peak plotted against time.
Mobile phase?
What components move in
can be liquid or gas
It moves hence ‘mobile’.
Stationary phase?
What components move over - stays still.
Types of chromatography?
Paer
Thin layer
High performance liquid
Gas
Examples of mobile and stationary phases?
Mobile phase is solvent in liquid state
Stationary phase is chromatography paper which is absorbant.
Stationary phase and mobile phase in papaer chromatography?
Stationary phase is paper.
Mobile phase is usually water.
What the detection in paper chromatography?
Naked eye or UV light.
Factors of paper chromatography?
Basic temperature.
Includes sample preperation.
Good for seperating water soluble inks.
Limited types of mobile phases can be used, so limit to what can be seperated.
Can be slower
Stationary and mobile phase of thin layer chromatography?
Stationary phase - Silica r aluminium based.
Mobile phase - solvents.
Whats the detection in thin layer chromatography?
UV light, chemical spray, iodine task.
Factors of thin layer chromatography?
Improvement to paper technique.
Good for - Monitoring reaction progress/identifying components in a mixture/purity determination/conditions for column seperation techniques.
Semi-quantative
Can be quicker than papaer chromatography.
What are the three basoc steps of paper/thin layer chromatography?
- Spotting
- Seperation
- Visualisation.
Mobile and stationary phases in high performance liquid chromatography?
Mobile - solvents/water/mixes
Stationary - silca based/ many types for certain applications.
High performance liquid chromatography information.
https://www.chemguide.co.uk/analysis/chromatography/hplc.html
Factors of high performance liquid chromatography?
Sample preperation
Precise injection volumes
Controlled composition/ flow of mobile phase
Oven temperature
Widely used in analytical laboratories
Quantify components - non volatile mixtures.
Retention times.
Mobile and stationary phase for gas chromatography?
Mobile phase - un-reactive gas
Stationary phases - polymer or liquid on an inert solid support
Factors of Gas chromatography?
Sample preperation
Precise injection volumes.
Temperature/gas flow control
Widely used in analytical laboratories
Quantifies components - volatile mixtures.
Has retention times
Where is the solvent level always?
Below the baseline.
Solvent front?
Furthest place along chromatogram solvent reaches.
Baseline?
Where samples of the substances are placed.
Solvent level?
Where the chosen solvent is placed.
