Why some oligo come with white powder and other oligo I see nothing?

Not all oligonucleotides dry identically and some can take a bit more time to completely go into solution than others. In addition, if the oligonucleotide solution freezes during the lyophilization process in the Speed-Vac it will appear as a white powder. Others will form clear crystal. Make sure to spin down every oligonucleotide prior to opening the tube for resuspension.<br />