According to some embodiments, a method for separating a first fraction of a single wall carbon nanotubes and a second fraction of single wall carbon nanotubes includes, but is not limited to: flowing a solution comprising the nanotubes into a dielectrophoresis chamber; applying a DC voltage, in combination with an AC voltage, to the dielectrophoresis chamber; and collecting a first eluent from the dielectrophoresis chamber, wherein the first eluent comprises the first fraction and is depleted of the second fraction, wherein the first and second fractions differ by at least one of conductivity, diameter, length, and combinations thereof.