This invention relates to a method of producing a purified polymer selected from the group consisting of PNAs, (poly)peptides, PNA chimera, peptide-DNA chimera, and derivatives thereof, wherein the polymer carries at least one lipophilic group and wherein the method comprises the following steps: (a) transferring a solution comprising the polymer carrying a lipophilic group to a lipophilic surface under conditions that allow binding of said lipophilic group to said lipophilic surface; (b) washing said surface under conditions that allow said binding to be maintained, wherein polymers not carrying said lipophilic group are removed; (c) washing said surface under conditions that break said binding; (d) collecting the washing solution from step (c); and (e) obtaining said purified polymer from said washing solution. Preferably, the lipophilic group is a protection group, or a label such as a fluorescent dye, or a linker, for example a linker suitable for immobilization on a support.