Unit 2C:
Evaluate the chromatographic techniques you have used in relation to the outcomes.
P6-
What is chromatography-
Chromatography is a method used by scientists for separating organic and inorganic
compounds so that they can be analysed and studied. By analysing a compound, a scientist
can figure out what makes up that compound. Chromatography is a great physical method for
observing mixtures and solvents.
What is a stationary and mobile phase?
The mobile phase could be a gas or liquid. Stationary phase: Substance that keep attached
over it or maintain in its bulk other chemicals by it s affinity to it, it does not move with a
passing fluid through it.
There are four main types of chromatography, here they are-
1) Paper chromatography
2) Thin layer chromatography (TLC)
3) Gas chromatography
4) High pressure liquid chromatography
Paper chromatography:
How does it work-
Capillary action makes the solvent travel up the paper, where it meets and dissolves the ink.
The dissolved ink (the mobile phase) slowly travels up the paper (the stationary phase) and
separates out into different components.
Advantages-
- It requires fever quantitative material.
- Separation of compounds in a short time.
- An analysis requires a low amount of sample
- Compare to other chromatography methods paper chromatography is a cheap
technique.
- Organic as well as inorganic compounds can be identified by paper chromatography
method.
- Setup of paper chromatography occupies less space than the other chromatographic
method.
- Easy to handle and setup.
- The less sample quantity required for the analysis.
- Cost-effective method.
Disadvantages-
, - Volatile substances cannot be separated using paper chromatography techniques.
- Paper chromatography cannot be compatible with large amounts of sample.
- Quantitative analysis is not useful in paper chromatography.
- Paper chromatography cannot be separated complex mixture.
- As compared to the HPLC or HPTLC, paper chromatography has less accuracy.
- Data cannot be saved for long periods.
What are the uses of paper chromatography?
It is used in the sequencing of DNA and RNA. Paper chromatography is used as a qualitative
analytical chemistry technique for identifying and separating colored mixtures like pigments.
It is used in scientific studies to identify unknown organic and inorganic compounds from a
mixture
Thin layer chromatography-
How does it work?
Thin-layer chromatography (TLC) is a chromatography technique used to separate non-
volatile mixtures. ... After the sample has been applied on the plate, a solvent or solvent
mixture (known as the mobile phase) is drawn up the plate via capillary action.
Advantages –
- This is a very easy way to separate the components.
- TLC is a sensitive method.
- In comparison to other separation techniques, very few types of equipment are used.
The components are separated in a very short time because the components will elute
rapidly.
- It is feasible to visualize all components of UV light.
- The non-volatile compounds are separated by the TCL method.
- The only small sample size is required in TLC, and it can be in microlitre.
- A comparison with standard material, tentative identification is possible.
- The components there in the complex mixture of samples are able to easily separate
and recovered by scratching the plate.
Evaluate the chromatographic techniques you have used in relation to the outcomes.
P6-
What is chromatography-
Chromatography is a method used by scientists for separating organic and inorganic
compounds so that they can be analysed and studied. By analysing a compound, a scientist
can figure out what makes up that compound. Chromatography is a great physical method for
observing mixtures and solvents.
What is a stationary and mobile phase?
The mobile phase could be a gas or liquid. Stationary phase: Substance that keep attached
over it or maintain in its bulk other chemicals by it s affinity to it, it does not move with a
passing fluid through it.
There are four main types of chromatography, here they are-
1) Paper chromatography
2) Thin layer chromatography (TLC)
3) Gas chromatography
4) High pressure liquid chromatography
Paper chromatography:
How does it work-
Capillary action makes the solvent travel up the paper, where it meets and dissolves the ink.
The dissolved ink (the mobile phase) slowly travels up the paper (the stationary phase) and
separates out into different components.
Advantages-
- It requires fever quantitative material.
- Separation of compounds in a short time.
- An analysis requires a low amount of sample
- Compare to other chromatography methods paper chromatography is a cheap
technique.
- Organic as well as inorganic compounds can be identified by paper chromatography
method.
- Setup of paper chromatography occupies less space than the other chromatographic
method.
- Easy to handle and setup.
- The less sample quantity required for the analysis.
- Cost-effective method.
Disadvantages-
, - Volatile substances cannot be separated using paper chromatography techniques.
- Paper chromatography cannot be compatible with large amounts of sample.
- Quantitative analysis is not useful in paper chromatography.
- Paper chromatography cannot be separated complex mixture.
- As compared to the HPLC or HPTLC, paper chromatography has less accuracy.
- Data cannot be saved for long periods.
What are the uses of paper chromatography?
It is used in the sequencing of DNA and RNA. Paper chromatography is used as a qualitative
analytical chemistry technique for identifying and separating colored mixtures like pigments.
It is used in scientific studies to identify unknown organic and inorganic compounds from a
mixture
Thin layer chromatography-
How does it work?
Thin-layer chromatography (TLC) is a chromatography technique used to separate non-
volatile mixtures. ... After the sample has been applied on the plate, a solvent or solvent
mixture (known as the mobile phase) is drawn up the plate via capillary action.
Advantages –
- This is a very easy way to separate the components.
- TLC is a sensitive method.
- In comparison to other separation techniques, very few types of equipment are used.
The components are separated in a very short time because the components will elute
rapidly.
- It is feasible to visualize all components of UV light.
- The non-volatile compounds are separated by the TCL method.
- The only small sample size is required in TLC, and it can be in microlitre.
- A comparison with standard material, tentative identification is possible.
- The components there in the complex mixture of samples are able to easily separate
and recovered by scratching the plate.
