a separate ion-pair reversed-phase high-performance liquid chromatographic ( hplc ) procedure using isocratic elution and electrochemical detection is employed to analyse in the same tissue extracts the catechols and 5-hydroxyindoles , 3,4-dihydroxyphenylalanine ( dopa ) , dopamine , norepinephrine , 3,4-dihydroxyphenylacetic acid , homovanillic acid , 4-hydroxy-3- methoxyphenylalanine , tryptophan , 5-hydroxytryptophan , serotonin and 5- hydroxyindolacetic acid .
C0041249
tryptophan
C0000578
5-hydroxytryptophan