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Why Didn't my Chromatography Experiment Work Properly?

I did a lab on column chromatography and thin layer chromatography, and our sample was a spinach extract.

I am trying to figure out if there is a correlation between the partition coefficient and the Rf used in thin layer chromatography. Is there one?

For the column chromatography we used a 9:1 hexane: acetone, thenn 1:1 hexane and acetone, then used methanol. We got three fractions and ideally the colors were supposed to be yellow for the 9:1, green for 1:1: and finally light green for methanol. Instead we got light yellow, light green, even lighter green. Why did that happen?

When I did the thin layer chromatography, only the spinach extract and the 9:1 actually moved up the plate. Nothing happened for the 1:1 and the methanol. I did repeatedly place the sample on the spot, but I don't understand what went wrong?

Solution Preview

Hello,

There is a very rough correlation between partition coefficient and Rf, but it would be difficult to quantify (put into actual numbers). As long as you are using the same kind of silica gel on the TLC plate as you are using on the column, the separations should be fairly similar. The common practice is to use the TLC to find the solvent ...

Solution Summary

Issues experienced by a student during a chromatography experiment are discussed in detail.

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