ISO 19563:2017

Determination of theanine in tea and instant tea in solid form using high-performance liquid chromatography

ISO 19563:2016 specifies a high-performance liquid chromatographic (HPLC) method for the determination of theanine content in tea (Camellia sinensis). It is applicable to both tea and instant tea samples. Separation of L- and D-theanine is not possible using this method; however, the L-enantiomer is the major form in tea.