Question

In a hypothetical column chromatography, the procedure for the separation of a polar and
non-polar compound calls for sequential elution with the following solvents: hexane,70:30 hexane:acetone, acetone, and 80:20 acetone:methanol. Why is it important to

follow this solvent order?

Answer 1

Initially we start with pure hexane which is a non polar solvent. Then we gradually increase the polarity of solvent by using 70:30 hexane:acetone, acetone. Finally we used most polar 80:20 acetone:methanol solvent. This will help us in achieving better separation. Initially when we use non polar solvent, the polar compound will remain attached to stationary phase and non polar compound will gradually come into mobile phase. When we increase the polarity of solvent system, the polar compound will slowly come into stationary pahse.