He made a slurry of silica gel with ethyl acetate to prepare his column, being careful yo tap it during loading in order to remove the air and compare the gel. Once ready, he put a bit of sand on top. He loaded about 1 gram of product that had been dissolved in 1 ml of ethyl acetate. He then began to elute with the 5:1 pentane/ethyl; acetate solvent combo and collected 8 fractions. what mistake was made here? what should he have done instead?