A method for electrochemical removal of acid-labile protecting groups on an electrode microarray using an organic solution is disclosed. The solution comprises a hydrazine derivative and a salt in an organic solvent. The hydrazine derivative has at least one hydrazine group having at least one hydrogen. The hydrazine derivative provides acidic reagent when an electrode is active and isolates the acidic reagent to the area around the active electrode. The salt is an organic salt or ionic liquid having a concentration sufficient to provide electrochemical conductivity under an applied voltage. During the applied voltage, acidic reagent is generated, which removes acid-labile protecting groups thereby allowing continued addition of monomers to build a custom microarray of oligonucleotides, peptides, or other polymers.