Rf value

[chemist]

Can anyone define Rf value? I would really appreciate it.

[tom jupille]

In thin layer chromatography or paper chromatography, Rf ("ratio of fronts") is the migration distance of a spot divided by the migration distance of the solvent front (both measured from the origin of the spot). If you want to relate it to other forms of liquid chromatography, Rf = 1/(1+k')

[chemist]

I'm calculating my Rf value as follows:
distance dye traveled divided by the distance the solvent traveled

[tom jupille]

that's correct.

[chemist]

What does your calculation mean? It really confuses me.

[tom jupille]

Here's a tutorial on HPLC. It explains what k' is.

http://www.lcresources.com/resources/getstart/

[chromatographer1]

ratio of fronts....... I like that.......

I learned that Rf meant....

Factor of retardation back in them olden days.

[pipettemonkey]

ratio of fronts....... I like that.......

I learned that Rf meant....

Factor of retardation back in them olden days.

Retention factor.

Analyte retention time / distance in HPLC or TLC is sensitive to the geometry of the column, run time, etc, . The retention factor (Rf) is a value for a compound that describes it's chromatography independantly of run, column length, etc. This value is useful for making comparisions while Rt is not.

[chemist]

What is Rt?

[Kostas Petritis]

Rt=Retention time

[chemist]

what is retention used for?
What category would it be used in the most?
What catetgory would it be used mainly for?

[tom jupille]

No, we're not going to do your homework for you.

Go through the tutorial here to find the answers:

http://www.lcresources.com/resources/getstart/