Author Topic: RF values  (Read 2203 times)

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SMACK_WHORE

  • Guest
RF values
« on: October 04, 2003, 10:20:00 AM »
ok i need a source of RF values.theres nada on this site about rf values except yada yada found rf value yada yada dmt etc.#
so anyone know a source of RF values????


ClearLight

  • Guest
They change...
« Reply #1 on: October 04, 2003, 12:47:00 PM »
The values vary depending upon the plate gel particle size, the solvent system, temperature, humidity and the type/form of the materials(freebase vs HCL salts.  Various rF values are reported for various compounds. What material where you looking to analyze. Normally you'll have a standard to run against, or you'll have an idea of the rF range based upon the literaure.

Need more data before you can be helped..


SMACK_WHORE

  • Guest
dunno really
« Reply #2 on: October 04, 2003, 01:44:00 PM »
dunno really swim was just thinkin bout doin some TL cromatography on some plant extracts, swim dont have anythin to use as a standard as swim thought that there where stadard rf values for stuff.
swim hasnt commited to a method yet but was hopin for a simple(ie only 1 solvent needed) method that an ametuer could perform and decifer..
if TLC/gettin RF values,turns out to be too difficult to pull off for a average jo i have another question....
how much Product would swim have to have to do a decent column cromatography, 10g?50g?100g?if this method was used i think swim would use a burette.
basicly swim is a micro chemist and is lookin for a method of checkin out whats in their "stuff"


pHarmacist

  • Guest
smack
« Reply #3 on: October 04, 2003, 02:42:00 PM »
I think that you have to read a bit more about the theory behind the chromatography before you ask such questions. Don't get me wrong, it's just that you seem to have overlooked the importnant details regarding basic principles of the subject, for instance there is no universal solvent-system. Sometimes you have to increase the polarity, sometimes you have to decrease it, depending on the nature of the substances you want to separate.

Take a look at the Vogel's third edition at the rhodium.ws, I think that it has a chromatography chapter.


Rhodium

  • Guest
flash column chromatography
« Reply #4 on: October 04, 2003, 07:17:00 PM »
Here you can read about flash column chromatography:

https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/flash.html



As a general rule, use 20 times as much silica gel as the weight of the sample you want to purify.