GB/T 32868-2025 "Nanotechnology — Thermogravimetric characterization of carbon nanotubes" is applicable to the characterization of various carbon nanotube samples (including single-walled and multi-walled carbon nanotubes). It replaces the previous version and expands the scope of application. The standard specifies characterization methods using thermogravimetric analysis (TGA) in inert or oxidizing environments, enabling the quantitative assessment of sample purity (including non-carbon impurity content such as metal catalysts) and qualitative analysis of thermal stability and uniformity. It clarifies requirements for sample preparation (sample amount, crucible selection, drying treatment), instrument calibration, and testing procedures, detailing key parameters such as heating rate and atmosphere control. The standard also introduces new references for crucible selection and specifications for handling outliers.