This document specifies a micro gas chromatography method for the on-line or offline determination of the content of five terpenes in biomethane, namely: alpha-pinene beta-pinene para-cymene limonene 3-carene. The method is specifically developed for these five compounds. Information about the compounds is given in Annex A. The method is applicable to the determination of individual amount fractions of the five terpenes from 1 ¼mol/mol up to and including 10 ¼mol/mol. With minor modifications it can also be used for terpene amount fractions above 10 ¼mol/mol.