By using solution-phase mid-IR spectroscopy, it was possible to obtain an estimate for the ratio, of the carbon atoms in the single-walled carbon nanotube backbone, to the carbon atoms in the end-groups and at defect sites of octadecylamido functionalized soluble single-walled carbon nanotubes. This analysis showed that the weight percentage of the octadecylamido functionality in the single-walled carbon nanotubes was about 50%.

End-Group and Defect Analysis of Soluble Single-Walled Carbon Nanotubes. M.A.Hamon, H.Hu, P.Bhowmik, S.Niyogi, B.Zhao, M.E.Itkis, R.C.Haddon: Chemical Physics Letters, 2001, 347[1-3], 8-12