- How does solubility affect RF value?
- What is the indication of RF values?
- Why do Rf values change with different solvents?
- Which pigment has the highest RF value?
- What does it mean if the RF value is 0?
- Can two compounds have the same Rf value?
- What are the factors that affect chromatography?
- What does higher RF value mean?
- Can an RF value be greater than 1?
- What are RF values?
- What are 3 factors that can affect RF values in TLC?
- Why is RF value important?
- Why do RF values differ?
- What are two major factors that can influence the distance the solute travels?
- What factors influence Rf values?
- What are good RF values?
How does solubility affect RF value?
The Rf values indicate how soluble the particular pigment is in the solvent by how high the pigment moves on the paper.
Two pigments with the same Rf value are likely to be identical molecules.
Small Rf values tend to indicate larger, less soluble pigments while the highly soluble pigments have an Rf value near to one..
What is the indication of RF values?
RF value (in chromatography) The distance travelled by a given component divided by the distance travelled by the solvent front. For a given system at a known temperature, it is a characteristic of the component and can be used to identify components.
Why do Rf values change with different solvents?
The eluting power of solvents increases with polarity. … Non-polar compounds move up the plate most rapidly (higher Rf value), whereas polar substances travel up the TLC plate slowly or not at all (lower Rf value).
Which pigment has the highest RF value?
PigmentRf value rangeRelative positionLutein0.22-0.28Below, or almost at the same level of, the highest greenViolaxanthin0.13-0.19Below, or almost at the same level of, the highest greenNeoxanthin0.04-0.09Below, or almost at the same level of, the highest green
What does it mean if the RF value is 0?
indicating the molecule did not moveThe Rf value ranges from 0 (indicating the molecule did not move up the plate at all) to 1 (indicating the molecule traveled all the way up the plate). Both the attraction of a molecule to the solvent and the attraction of the molecule to the stationary phase will affect the Rf value.
Can two compounds have the same Rf value?
The larger an Rf of a compound, the larger the distance it travels on the TLC plate. … If two substances have the same Rf value, they are likely (but not necessarily) the same compound. If they have different Rf values, they are definitely different compounds.
What are the factors that affect chromatography?
Retention factor values in thin layer chromatography are affected by the absorbent, the solvent, the chromatography plate itself, application technique and the temperature of the solvent and plate.
What does higher RF value mean?
A high Rf (Ie 0.92) would refer to a substance that is very non-polar. Ie that substance moved a 92% of the entire distance the solvent traveled. A low Rf value (0.10) would refer to a substance that is very polar. IE that substance was only able to move 10% of the entire distance the solvent traveled.
Can an RF value be greater than 1?
Why or why not? -In order to have an Rfvalue greater than 1 the pigment would have to move further than the solvent. Since the pigment is carried by the solvent an Rfgreater than one is not possible.
What are RF values?
The Rf value is defined as the ratio of the distance moved by the solute (i.e. the dye or pigment under test) and the distance moved by the the solvent (known as the Solvent front) along the paper, where both distances are measured from the common Origin or Application Baseline, that is the point where the sample is …
What are 3 factors that can affect RF values in TLC?
Rf values and reproducibility can be affected by a number of different factors such as layer thickness, moisture on the TLC plate, vessel saturation, temperature, depth of mobile phase, nature of the TLC plate, sample size, and solvent parameters. These effects normally cause an increase in Rf values.
Why is RF value important?
Rf value stands for the retardation factor value. It tells us how far the unknown pigment traveled in relation to the distance the solvent traveled. The Rf value is useful for scientists because it allows scientists to identify the pigment by comparing its Rf value to that of a known standard.
Why do RF values differ?
The larger an Rf of a compound, the larger the distance it travels on the TLC plate. When comparing two different compounds run under identical chromatography conditions, the compound with the larger Rf is less polar because it interacts less strongly with the polar adsorbent on the TLC plate.
What are two major factors that can influence the distance the solute travels?
The more soluble the solute in the nonpolar, organic, mobile phase, the farther it will move.
What factors influence Rf values?
factors which affect Rf value are:-• The solvent system and its composition. Temperature. The quality of the paper. Distance through which the solvent runs.
What are good RF values?
The best Rf (retention or retardation factor) lies between 0.3 and 0.7. If you want the Rf of your TLC spot to be smaller, i.e., the spot to be lower down on the plate, you must decrease the eluent polarity.