Very high purity single-walled carbon nanotubes (SWNTs) were obtained from HiPco SWNT samples containing Fe particles by a two-step purification process. The raw and purified samples were characterized using high resolution transmission electron microscopy (HRTEM), Raman spectroscopy and thermogravimetric analysis (TGA). The purified sample consists of similar to0.4% Fe and the process does not seem to introduce any additional defects. The N-2 adsorption isotherm studies at 77 K reveal that the total surface area of the purified sample increases to 1587 m(2)/g from 567 m(2)/g for the raw material, which is the highest value reported for SWNTs. (C) 2002 Elsevier Science B.V. All rights reserved.