Fichas
TLC and Gas Chromatography
Fichas del conjunto (27)
- 1What is the TLC plate?TLC plate coated with a thin layer of solid silica adsorbent
- 2What's an adsorbent?Substance which adsorbs another
- 3Which is the stationary phase in TLC?The adsorbent
- 4What is RfRetention factor
distance by component/distance by solvent front - 5How do you identify a component using its Rf value?Compare to standard values obtained using same solvent system and adsorbent
- 6TLC Step 1.Take a TLC plate.
Draw a line across the plate about 1cm from end of one plate. This is the base line. - 7Step 2.Using a capillary tube, spot a small amount of a solution of the sample onto the base line of the plate.
- 8Step 3.Prepare a chromatography tank for the TLC plate. This can be made from a small beaker with a watch glass placed on the top.
- 9Step 4.Pour some solvent into the beaker to a depth of about 0.5cm
- 10Step 5.Place the prepared TLC plate in the beaker, making sure the solvent doesn't cover the spot. Cover the beaker with the watch glass and leave to stand.
- 11Step 6.Allow the solvent to rise up the plate until it is about 1cm below the top of the plate. Remove the plate from the beaker and immediately mark the solvent front with a pencil. Allow the plate to dry.
- 12Step 7.If there are any visible spots, circle them with a pencil.
- 13What 2 methods can you use to see difficult to see spots?Hold a UV lamp over the plate.
Spray the plate with iodine. - 14What is GC useful for separating and identifying?Volatile organic compounds in a mixture
- 15What does GC tell you about the organic compounds? (2)Their identity
Their concentrations in a sample - 16What does GC separate components based on?How soluble they are in the liquid stationary phase
- 17The more soluble the component in the liquid phase --The slower it moves through the column
- 18What is the retention time?The time it takes each component to travel through the column from time of injection
- 19How do you utilise the retention times to identify the components in a sample?Compare to known retention time values
- 20What are peak integrations?The areas under each peak
- 21What can this tell you?The concentration of components in a sample
- 22Working out concentration of components Step 1.Prepare STD. Sol of known conc. of compound being investigated
- 23Step 2.Obtain gas chromatograms for each STD sol.
- 24Step 3.Plot a calibration curve of peak integrations against concentration.
- 25What kind of calibration is this?External Calibration
- 26Step 4.Obtain a gas chromatograph of the compound being investigated under the same conditions
- 27Step 5.Use the calibration curve to measure the concentration of the compound.
Información
- Descripción
- Fichas sobre TLC and Gas Chromatography, creado por josephw weetch el 02/06/2018.
- Creado por
- josephw weetch
- Visitas
- 1
- Valoración