Separtion by paper chromatography

Click For Summary

Discussion Overview

The discussion revolves around the principles and practices of paper chromatography, specifically focusing on the importance of solvent front management and sample application techniques. Participants explore the implications of these factors on the accuracy and clarity of separation results.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that allowing the solvent front to reach the top of the chromatogram disrupts the ability to calculate ratios of component movement relative to the solvent.
  • Another participant emphasizes that if the solvent front reaches the top, it invalidates the distance ratios, necessitating a restart of the experiment.
  • A question is raised regarding the importance of keeping indicator spots small, suggesting that it may relate to the efficiency of separation.
  • Concerns are expressed about using too much sample, which can lead to overlapping streaks that complicate the identification of individual components.
  • A participant questions the rationale for using acid-base indicators instead of more common substances, proposing that it may be due to their colorless nature in solution, which complicates tracking their movement.

Areas of Agreement / Disagreement

Participants express differing views on the implications of solvent front management and sample size, indicating that there is no consensus on the best practices or the reasons behind certain methodologies.

Contextual Notes

Limitations include assumptions about the behavior of components in chromatography and the definitions of terms such as "efficiency" and "overlap," which are not explicitly clarified in the discussion.

Who May Find This Useful

This discussion may be of interest to students and practitioners in chemistry and biochemistry, particularly those involved in experimental techniques related to chromatography.

moonlight1
Messages
8
Reaction score
0
Hi does anyone know why it is imporatnt not to permit the solvent front to reach the top of the chromatogram?
 
Chemistry news on Phys.org
When the solvent reaches the top, it totally screws up your ratios. Before reaching the top, you can say the components move X distance for every Y distance the solvent moves. Now that the solvent can't move anymore, that ratio doesn't apply, so you can no longer calculate that ratio. You would have to start over again.
 
Then why is it impotant to keep the indictor spots very small? is it beacuse separation is efficient?
 
If you use too much sample for the spots, you get huge streaks, and the different parts can overlap. Suppose 3 dots are supposed to come out, one is blue, one is yellow, and one is green. If you use too much, you'll get big yellow and blue streaks that overlap to make a greenish area. Is the desired green component even there, or is the green area just overlap of yellow and blue? How can you tell?
 
Whats the point to use acid-base indicators as the subanctes instead of more commom substances such as sugar or salt?

is it casue its colorless in soultion so we canot track their movement
 

Similar threads

Why Do Enantiomers Interact Differently with Chiral Compounds?
  • · Replies 3 ·
Replies
3
Views
2K
Separation Through chromatography
  • · Replies 5 ·
Replies
5
Views
2K
Protocol and solvent help needed for gel-permeation chromatography
  • · Replies 11 ·
Replies
11
Views
7K
Gas Chromatography: Varian CP 3800 GC
  • · Replies 4 ·
Replies
4
Views
8K
Ether Synthesis by Sn2 displacement
  • · Replies 1 ·
Replies
1
Views
3K
Why during chromatography must the paper NOT touch the sides
  • · Replies 1 ·
Replies
1
Views
8K
Chromatography Applications and Advantages
  • · Replies 5 ·
Replies
5
Views
4K
Chromatography as a separation techinique
  • · Replies 4 ·
Replies
4
Views
3K
Can Thin Layer Chromatography Effectively Isolate Impurities from Ester Samples?
  • · Replies 5 ·
Replies
5
Views
3K
Solutes with very high melting points
  • · Replies 4 ·
Replies
4
Views
2K