Two liquid chromatography techniques for single-walled carbon nanotube (SWNT) separation, size-exclusion chromatography (SEC), and ion-exchange chromatography (IEX) are combined to obtain small diameter semiconducting SWNTs with defined length and chirality. It is observed that these tubes elutes in the IEX separation in the order of (6,4), (9,1), (6,5), (8,3), and (7,5). The improved resolution allows clear separation of (6,5) from (9,1), two semiconducting SWNTs with identical diameter but different chirality.