Methods for deprotecting and derivatizing oligonucleotides that are non-covalently bound to a solid support are described. The methods include providing a plurality of oligonucleotides linked to one or more hydrophobic separation functions, wherein the plurality includes protected oligonucleotides, precipitating the plurality of oligonucleotides on a hydrophobic solid support using an organic solvent to produce non-covalently immobilized oligonucleotides, and deprotecting the immobilized oligonucleotides.