a new method is described for the determination of catecholamines and their precursor ( 3,4-dihydroxyphenylalanine ) , and separately of their catechol metabolites ( 3,4-dihydroxymandelic acid , 3,4-dihydroxyphenylacetic acid , 3,4-dihydroxyphenylethylene glycol and 3,4-dihydroxyphenylethanol ) in urine .
C0007412
catecholamines
C0013023
dihydroxyphenylalanine