The estimation of urinary catecholamines has assumed clinical significance mainly because of its value in the diagnosis of phaeochromocytoma (Engel and Euler, 1950; Euler, 1951). Since biological methods have obvious limitations for routine work, various chemical methods have been developed (Lund, 1950; Pekkarinen and Pitkanen, 1955; Euler and Floding, 1955a, b). They are based on the same prin...