Hexamethylene tetramine (hexamine) in phenol‐formaldehyde and urea‐formaldehyde moulding compounds can be determined by non‐aqueous titration in acetic acid solution with perchloric acid. Phenolic compounds may be dissolved directly in glacial acetic acid and the hexamine may be titrated. However, hexamine must first be extracted from dry urea‐formaldehyde samples with chloroform before titration as the resin interferes with the titration. Nuclear magnetic resonance spectroscopy may also be used to determine the hexamine content of the extracted solution.