Question

1. Below is a picture of a TLC plate by a student using this technique and developing a TLC plate for the first time. You can see that the yellow compound from the spot is actually traveling downward and into the solution, as opposed to upward with a capillary action. The reason for this failed attempt is a major error in the performed technique,acommon mistake about which the student was warned multiple times prior to the lab work. What did she do wrong?

Answer 1

In a TLC technique we take a base line on which spots of reactants and reaction mixture are put. The TLC plate is then kept in a TLC chamber in which little amount of solvent is kept to elute the TLC. The base line of the TLC should be always above the solvent. Here, the student has dipped the TLC plate in the solvent above than base line which has resulted in the dissolution of base spots in the solvent, thus, base spots are coming down instead of going up