Separating different types of nanotubes from one another includes providing a sample of heterogeneous nanotubes comprising a first and second type of carbon nanotube; providing a first type of molecule; introducing the first type of molecule to the sample; binding the first type of molecule to the first type of carbon nanotube; and separating the first type of carbon nanotube from the sample. A second type of molecule may be introduced to the sample followed by binding the second type of molecule to the second type of carbon nanotube; and separating the second type of carbon nanotube from the sample. The sample may comprise a third type of carbon nanotube. A third type of molecule may be introduced to the sample followed by binding the third type of molecule to the third type of carbon nanotube; and separating the third type of carbon nanotube from the sample.