Photochemical Decomposition of Catecholamines—ii.* the Extent of Aminochrome Formation From Adrenaline, Isoprenaline and Noradrenaline Induced by Ultraviolet Light

During photochemical decomposition (Λ= 254 nm) adrenaline, isoprenaline and noradrenaline in aqueous solution are converted to the corresponding aminochrome for 65, 56 and 35%,. respectively. In determining this conversion, photochemical instability of the aminochromes is taken into account. Irradiations are performed in such dilute solutions that the neglect of the inner filter effect is permissible. Furthermore. quantum yields for the decomposition of the aminochromes in aqueous solution are given.