1990766
Description
Mind Map by Tom Johnson, updated more than 1 year ago
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Created by Tom Johnson
almost 10 years ago
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Chromatography
- Chromatography is used to identify substances in a mixture/sample
- Gas Chromatography
- How Does it Work?
- 1) A gas is used to transport
substances through a column
packed with solid metal
- 2) The substances (compounds) travel at
different rates through the metal
column and are separated out
during the journey
- 3) The substances all reach a
detector at the end of the
metal column at different
times
- 4) The time taken for the
substances to get to the detector
from entering the column is called
the "retention time"
- 5) A recorder in the detector creates a
graph with the x axis measuring time. Every
time a new substance reaches the detector,
it creates a peak on the graph
- 6) This graph is called a "gas chromatograph"
and the number of peaks shows the number of
different compounds in the sample
- 7) The position of the peaks on the
graph shows the retention time for
each substance
- 7) The position of the peaks on the
graph shows the retention time for
each substance
- 6) This graph is called a "gas chromatograph"
and the number of peaks shows the number of
different compounds in the sample
- 5) A recorder in the detector creates a
graph with the x axis measuring time. Every
time a new substance reaches the detector,
it creates a peak on the graph
- 4) The time taken for the
substances to get to the detector
from entering the column is called
the "retention time"
- 3) The substances all reach a
detector at the end of the
metal column at different
times
- 2) The substances (compounds) travel at
different rates through the metal
column and are separated out
during the journey
- 1) A gas is used to transport
substances through a column
packed with solid metal
- What Does it Do?
- Gas Chromatography is used to separate out and identify a mixture of compounds when moving
through a gas and identify the substances present
- Gas Chromatography is used to separate out and identify a mixture of compounds when moving
through a gas and identify the substances present
- How Does it Work?
- Chromatography Using
Filter Paper
- What Does it Do?
- Chromatography using filter paper is used of commonly separating out
substances in a sample, commonly artificial colourings. Eg. a food colouring
might contain one dye or a mixture of dyes. Chromatography will help
separate out these dyes
- Chromatography using filter paper is used of commonly separating out
substances in a sample, commonly artificial colourings. Eg. a food colouring
might contain one dye or a mixture of dyes. Chromatography will help
separate out these dyes
- How Does it Work?
- 1) A pencil baseline is drawn onto a strip of filter
paper with a drop of food colouring (or choice of
sample) placed upon this baseline
- 2) The filter paper is then rolled up and placed in a
beaker with the water of solvent of choice only just
touching the filter paper. The baseline is to be kept
above the water level
- 3) The solvent will then seep up the filter paper,
bypassing the baseline and taking the dyes from
the baseline with it
- 4) The mixture of dyes will then begin to separate due
to the different dyes absorbing into the filter paper at
different rates (heights on the filter paper)
- 5) The filter paper is then known as a "chromatogram" and
displays the different dyes on it due to the different colours at
varying heights up the filter paper
- 6) A chromatogram with 4 spots means AT LEAST 4
different dyes, not EXACTLY 4 different dyes due to
there being the possibility of multiple dyes absorbing in
the same place
- 6) A chromatogram with 4 spots means AT LEAST 4
different dyes, not EXACTLY 4 different dyes due to
there being the possibility of multiple dyes absorbing in
the same place
- 5) The filter paper is then known as a "chromatogram" and
displays the different dyes on it due to the different colours at
varying heights up the filter paper
- 4) The mixture of dyes will then begin to separate due
to the different dyes absorbing into the filter paper at
different rates (heights on the filter paper)
- 3) The solvent will then seep up the filter paper,
bypassing the baseline and taking the dyes from
the baseline with it
- 2) The filter paper is then rolled up and placed in a
beaker with the water of solvent of choice only just
touching the filter paper. The baseline is to be kept
above the water level
- How to Work Out the "Rf" Value for Each Chemical (Substance)
- Rf= Distance Travelled By Substance (Eg. Food Colouring) ÷ Distance Travelled by Solvent (eg. Water)
- Rf= Distance Travelled By Substance (Eg. Food Colouring) ÷ Distance Travelled by Solvent (eg. Water)
- 1) A pencil baseline is drawn onto a strip of filter
paper with a drop of food colouring (or choice of
sample) placed upon this baseline
- What Does it Do?
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