Standard Rf Values - Biology (Photosynthesis)

AI Thread Summary
Standard Rf values for plant pigments vary with the solvent used, with nonpolar pigments traveling farther in nonpolar solvents. A plant physiology manual identifies specific Rf values for pigments extracted from spinach leaves using hexane and chromatographed with a petroleum ether-acetone-chloroform mixture. The Rf values noted are carotene at 0.98, chlorophyll a at 0.59, chlorophyll b at 0.42, pheophytin at 0.81, xanthophyll 1 at 0.28, and xanthophyll 2 at 0.15. The color of the pigment bands can assist in identification, with carotene appearing orange and chlorophylls in various shades of green. Accurate identification relies on comparing results to these established standards.
Christina-
Messages
11
Reaction score
0
Would anyone happen to know where I could find the standard Rf values (for Chlorophyll a, Chlorophyll b, Xanthophyll, and Carotene) if varsol is the solvent? I'm trying to identify those plant pigments via Paper Chromatography, and I'd like to compare my results to the standards. The problem is, I've been looking and can't find it.
 
Physics news on Phys.org
This is what you can use:

"Rf values will be unique for each solvent. However, the general order of the Rf values should be the same because the more nonpolar pigments move farther in nonpolar organic solvents.
A recent plant physiology manual (Reiss 1994) identifies six pigments from spinach leaves extracted with hexane and chromatographed with petroleum ether-acetone-chloroform (3:1:1) on silica-gl chromatography. 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. Carotene is orange. Chorophylls are green. Chlorophyll a is a blue-green. Chlorophyll b is a yellow-green. Xanthophylls are yellow. Phaeophytin is chlorophyll lacking the central magnesium ion. Pheophytin is an olive-green."

Source: http://madsci.org/posts/archives/2001-12/1008377272.Bt.r.html
(Original source cited: Reiss, Carol 1994. Experiments in Plant Physiology. Englewood Cliffs, NJ: Prentice Hall.)
 
I don't get how to argue it. i can prove: evolution is the ability to adapt, whether it's progression or regression from some point of view, so if evolution is not constant then animal generations couldn`t stay alive for a big amount of time because when climate is changing this generations die. but they dont. so evolution is constant. but its not an argument, right? how to fing arguments when i only prove it.. analytically, i guess it called that (this is indirectly related to biology, im...
Back
Top