Question

Column chromotography lab question?

Once the chromatographic column has been prepared, why is it important to allow the level of the liquid in the column to drop to the level of the alumina before applying the solution of the compound to be separated?

Answer 1

In wet packing of chromatographic coloumn we use eluent to wet the entire coloumn before the application of compound. It is very important to drain the excess eluent which is in above the stationary phase. Why it is important is our compound which has much more non polar compound can be dissolved in the eluent and hence it can affect separation of individual compounds. Also if you add compound with excess of solvent the compound will not adsorbed over Silicagel/alumina hence it will leads to improper separation of bands.