Pearson Edexcel NFQ BTEC Level 3 National
Extended Diploma in Applied Science
Unit 2C: Undertake chromatographic techniques to
identify components in mixtures
Name: Isbat Uddin
ID: 11208069
Scenario:
I am a newly appointed technical assistant at a large chemical plant, Chemcalequip.
As part of my induction period and to progress in my role, I have to demonstrate skills
in a range of practical procedures and techniques. The company is often required to
identify substances. I need to demonstrate that I can carry out different
chromatographic techniques to separate and identify components in mixtures. In a
report of the techniques I have used, I will need to explain the techniques, analyse
and evaluate my results and suggest improvements.
Introduction:
The laboratory process whereby the mixture is separated into its components
through the application of the differences in physical and chemical characteristics of
the components is referred to as chromatography. The principle involved in paper
chromatography depends on the fact that substances have different distributions in
the stationary phase and mobile phase (solvent). This means that substances with
high solubility in the solvent move faster and farther than those with less affinity
towards the solvent but greater affinity to the paper.
Paper chromatography finds wide applications in the field of science as it enables
one to identify an unknown substance by comparing the distance it moves against
the solvent distance. The distance moved by each substance can easily be
determined using the retention factor (Rf).
Rf = distance travelled by compound / distance travelled by solvent front
The retention factor (Rf) is used to compare how far substances travel under the
same chromatographic conditions. Substances with higher Rf values travel further in
the mobile phase, while lower Rf values indicate greater attraction to the stationary
phase.
,For example, if a pigment travelled 4.0 cm and the solvent front travelled 8.0 cm, the
Rf value would be calculated as 0.50. This allows unknown substances to be
identified by comparing their Rf values with known literature values obtained under
the same experimental conditions. Rf values are specific to the experimental
conditions, meaning that factors such as solvent composition, temperature, and
stationary phase type can significantly influence results. Therefore, accurate
technique and consistent conditions are essential for valid comparison with reference
data.
In this study, paper chromatography will be applied for separation of the various
pigments present in plant material chlorophyll. Through analysing the distance
traveled by the various pigments and determining their Rf values, it becomes
possible to identify the different components present in the plant extract.
The effectiveness and accuracy of chromatographic methods depend on the nature
of the stationary phase applied. The paper chromatography method has lower
accuracy compared to the thin layer chromatography technique owing to the fact that
the former involved fibrous diffusion. The research study presents an opportunity to
compare the two types of chromatographic methods. In industrial laboratories such
as Chemicalequip, chromatography is essential for quality control, identification of
unknown substances and monitoring the purity of chemical products.
Theory and Applications of Chromatography
Chromatography is one of the many separation techniques which rely on differences
in physical and chemical properties to separate components of mixtures. The
process relies on differences in interaction between the different materials and two
phases namely; the stationary phase (such as paper or TLC plates) and the mobile
phase (solvent).
Materials that have a higher solubility and lesser attraction to the stationary phase
are able to migrate further compared to others that have lower solubility but greater
attraction. As such, the components of a mixture can be separated, thereby
facilitating the identification of unknown materials.
Chromatography is applied in forensics, pharmaceuticals, food testing among many
others. One area where chromatography can be applied in forensics is during the
examination of ink samples for any evidence of forgery.
Each part of the mixture can be quantitatively analysed by the help of retention
factors (Rf) and hence comparing materials will become possible in the same
conditions, increasing precision in their identification.
, This project aims at investigating several types of chromatography and applying them
in the process of separating compounds found in plants and amino acid solution. The
process will be analysed with the use of retention factors (Rf).
Practical 1: Chromatography of Chlorophyll
Aim: The aim of this experiment is to use paper chromatography to separate the
different pigments present in chlorophyll extracted from spinach leaves and identify
the components by analysing their movement and calculating their retention factor
(Rf) values.
Equipment:
● Fresh green leaves (spinach)
● Propanone
● Pipette
● Sand
● Mortar and pestle
● Chromatography paper
● Capillary tube
● Pencil
● 100 ml beaker
● Wooden splint
● Scissors
● Ruler
● Drying surface
Health and Safety:
● Safety goggles and lab coats were used all through the process to minimise
exposure of the eyes to the solvent and protect from stains due to the ink.
● Petroleum ether/propanone (70:30) and 100% petroleum ether were used as
solvents and were handled carefully because they are flammable and produce
harmful vapours.
● The test was performed in a ventilated environment to decrease chances of
inhaling solvent vapours.
● Glassware was treated carefully so that it would not crack and injure anyone.
● The experimental equipment was set up so that the solvent level remained
below the baseline on the chromatography paper.
Extended Diploma in Applied Science
Unit 2C: Undertake chromatographic techniques to
identify components in mixtures
Name: Isbat Uddin
ID: 11208069
Scenario:
I am a newly appointed technical assistant at a large chemical plant, Chemcalequip.
As part of my induction period and to progress in my role, I have to demonstrate skills
in a range of practical procedures and techniques. The company is often required to
identify substances. I need to demonstrate that I can carry out different
chromatographic techniques to separate and identify components in mixtures. In a
report of the techniques I have used, I will need to explain the techniques, analyse
and evaluate my results and suggest improvements.
Introduction:
The laboratory process whereby the mixture is separated into its components
through the application of the differences in physical and chemical characteristics of
the components is referred to as chromatography. The principle involved in paper
chromatography depends on the fact that substances have different distributions in
the stationary phase and mobile phase (solvent). This means that substances with
high solubility in the solvent move faster and farther than those with less affinity
towards the solvent but greater affinity to the paper.
Paper chromatography finds wide applications in the field of science as it enables
one to identify an unknown substance by comparing the distance it moves against
the solvent distance. The distance moved by each substance can easily be
determined using the retention factor (Rf).
Rf = distance travelled by compound / distance travelled by solvent front
The retention factor (Rf) is used to compare how far substances travel under the
same chromatographic conditions. Substances with higher Rf values travel further in
the mobile phase, while lower Rf values indicate greater attraction to the stationary
phase.
,For example, if a pigment travelled 4.0 cm and the solvent front travelled 8.0 cm, the
Rf value would be calculated as 0.50. This allows unknown substances to be
identified by comparing their Rf values with known literature values obtained under
the same experimental conditions. Rf values are specific to the experimental
conditions, meaning that factors such as solvent composition, temperature, and
stationary phase type can significantly influence results. Therefore, accurate
technique and consistent conditions are essential for valid comparison with reference
data.
In this study, paper chromatography will be applied for separation of the various
pigments present in plant material chlorophyll. Through analysing the distance
traveled by the various pigments and determining their Rf values, it becomes
possible to identify the different components present in the plant extract.
The effectiveness and accuracy of chromatographic methods depend on the nature
of the stationary phase applied. The paper chromatography method has lower
accuracy compared to the thin layer chromatography technique owing to the fact that
the former involved fibrous diffusion. The research study presents an opportunity to
compare the two types of chromatographic methods. In industrial laboratories such
as Chemicalequip, chromatography is essential for quality control, identification of
unknown substances and monitoring the purity of chemical products.
Theory and Applications of Chromatography
Chromatography is one of the many separation techniques which rely on differences
in physical and chemical properties to separate components of mixtures. The
process relies on differences in interaction between the different materials and two
phases namely; the stationary phase (such as paper or TLC plates) and the mobile
phase (solvent).
Materials that have a higher solubility and lesser attraction to the stationary phase
are able to migrate further compared to others that have lower solubility but greater
attraction. As such, the components of a mixture can be separated, thereby
facilitating the identification of unknown materials.
Chromatography is applied in forensics, pharmaceuticals, food testing among many
others. One area where chromatography can be applied in forensics is during the
examination of ink samples for any evidence of forgery.
Each part of the mixture can be quantitatively analysed by the help of retention
factors (Rf) and hence comparing materials will become possible in the same
conditions, increasing precision in their identification.
, This project aims at investigating several types of chromatography and applying them
in the process of separating compounds found in plants and amino acid solution. The
process will be analysed with the use of retention factors (Rf).
Practical 1: Chromatography of Chlorophyll
Aim: The aim of this experiment is to use paper chromatography to separate the
different pigments present in chlorophyll extracted from spinach leaves and identify
the components by analysing their movement and calculating their retention factor
(Rf) values.
Equipment:
● Fresh green leaves (spinach)
● Propanone
● Pipette
● Sand
● Mortar and pestle
● Chromatography paper
● Capillary tube
● Pencil
● 100 ml beaker
● Wooden splint
● Scissors
● Ruler
● Drying surface
Health and Safety:
● Safety goggles and lab coats were used all through the process to minimise
exposure of the eyes to the solvent and protect from stains due to the ink.
● Petroleum ether/propanone (70:30) and 100% petroleum ether were used as
solvents and were handled carefully because they are flammable and produce
harmful vapours.
● The test was performed in a ventilated environment to decrease chances of
inhaling solvent vapours.
● Glassware was treated carefully so that it would not crack and injure anyone.
● The experimental equipment was set up so that the solvent level remained
below the baseline on the chromatography paper.
