Can an Rf be greater than 1?
Can an Rf be greater than 1?
Long Answer: Rf is the “Retardation Factor”, which is the ratio of the distance traveled by a compound in a mobile phase compared with the distance traveled by the front of the mobile phase itself. It is always greater than or equal to zero, and less than or equal to 1.
How do you identify the pigments in chromatography?
Four primary pigments of green plants can easily be separated and identified using a technique called paper chromatography. These pigments include two greenish pigments called chlorophylls and two yellowish pigments called carotenoids. Pigments are separated according to differences in their relative solubilities.
Would you expect the Rf value of a pigment to be the same if a different solvent were used explain?
The Rf value of a pigment would not be the same if a different solvent were used because each solvent is different. The solubility and size of the specific solvent will produce different results (No author mentioned.
Which pigment has the highest Rf value?
Chlorophyll a
From this, we can deduce that carotenes are the least polar pigments (no polar groups), and xanthophylls are the most polar (two alcohol groups, one at each end of the molecule)….Explanation.
| Pigment | Rf value |
|---|---|
| β-carotene | 0.98 |
| Chlorophyll a | 0.59 |
| Chlorophyll b | 0.42 |
| Anthocyanins | 0.32-0.62 |
What is r1 value?
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 pigments have different RF values?
The solvent carries the dissolved pigments as it moves up the paper. The pigments are carried at different rates because they are not equally soluble. A pigment that is the most soluble will travel the greatest distance and a pigment that is less soluble will move a shorter distance.
What is pigment chromatography?
Paper chromatography is a useful technique in the separation and identification of different plant pigments. The solvent carries the dissolved pigments as it moves up the paper. The pigments are carried along at different rates because they are not equally soluble.
How do you calculate Rf value of pigment?
Rf = (distance moved by pigment)/ (distance moved by solvent)
- Rf for carotenes = 9.7cm/9.8cm = 0.99.
- Rf for xanthophylls = 7.2cm/9.8cm = 0.73.
- Rf for chlorophyll a = 5.1cm/9.8cm = 0.52.
- Rf for chlorophyll b = 3.7cm/9.8cm = 0.38.
Why some pigments have larger Rf value?
A pigment that is the most soluble will travel the greatest distance and a pigment that is less soluble will move a shorter distance. The distance the pigment travels is unique for that pigment in set conditions and is used to identify the pigment. The ratio is the Rf (retention factor) value.
What is the Rf value of lycopene?
The lycopene standards have calculated Rf values of 0.20 each. Lycopene is supposed to carry the color red. It did appear so for most of the parts, with the exception being in some areas it was too light in color. Therefore, the Rf value for the lycopene standard was found to be 0.20.
What’s the RF value?
What are the pigments and their RF’s?
The pigments and their Rf’s were: carotene – 0.98. chlorophyll a – 0.59. chlorophyll b – 0.42. pheophytin – 0.81. xanthophyll 1 – 0.28. xanthophyll 2 – 0.15. The color of the bands can be a general guide to identify the pigments.
What is the Rf value of xanthophyll?
You can obtain Rf values for each of your pigment lines using the equation in Figure 1. The literature reports the following Rf values for each component: Rf = 0.16 for xanthophyll, Rf = 0.32 for chlorophyll b, Rf = 0.44 for chlorophyll a, and Rf = 0.95 for β- carotene.
What is the Rf value of chlorophyll b?
Rf for chlorophyll a = 5.1cm/9.8cm = 0.52. Rf for chlorophyll b = 3.7cm/9.8cm = 0.38. Click to see full answer. Beside this, what are the RF values of pigments? You can obtain Rf values for each of your pigment lines using the equation in Figure 1.
What is the Rf value of the dye?
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
