The Biochrom 30 Amino Acid Analyser is a well established analytical instrument for clinical diagnosis as its IVD approval allows the diagnosis of inborn errors of metabolism such as Phenylketonuria. This robust and reliable instrument is also capable of other types of applications far from the clinical market e.g. its usage in the food industry allows routine analysis of amino acid content in food and feedstuff in quality control laboratories. The Biochrom 30 can also be used for analysing rare, unusual amino acids or derived molecules for research purposes. In order to develop new methods for analysing molecules of interest in the scientific market, a new application has been developed to analyse the theanine content in green tea leaves. Theanine is a molecule derived from the amino acid glutamine and is usually found in tea (infusions of Camellia sinensis), and also in the basidiomycete mushroom Boletus badius. Because it can enter the brain, theanine has psychoactive properties. Theanine has been shown to reduce mental and physical stress, may produce feelings of relaxation, and improves cognition and mood when taken in combination with caffeine. These effects are believed to be caused by the ability of theanine to increase GABA production in the brain. The chemical structure of theanine allows it to be separated and detected in green tea samples using a Biochrom 30 Amino Acid Analyser.