Darcy got nice separation for her 3-component mixture on a tlc plate that was developed in pentane:ethyl acetate (5:1, v/v). Unfortunately, his column separation was woefully unsuccessful...everything quickly came pouring off the column together. Here’s what he did: He made a slurry of silica gel with ethyl acetate to prepare his column, being careful to tap it during loading in order to remove the air and compact 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 did Darcy make here? What should he have done instead?