This Technical Specification provides guidelines for the characterization of SWCNT-containing samples by the use of TGA, performed in an air environment. Guidance is provided on purity assessment of SWCNT samples through a quantitative measure of the non-carbon impurity (i.e. metal catalyst) level within the material.In addition, this technique can provide a qualitative assessment of the thermal stability and homogeneity of the SWCNT-containing sample. Additional characterization techniques are required to confirm the presence of SWCNTs and to verify the composition of the metallic impurities present.