b using octanesulfonic acid for ion pairing and by optimising ionic strength , ph and methanol concentration of the mobile phase , separation was achieved of 3,4-dihydroxyphenylalanine ( dopa ) , 3,4-dihydroxyphenylacetic acid ( dopac ) , norepinephrine ( ne ) , epinephrine ( epi ) , and dopamine ( da ) .
C0028351
norepinephrine
C0014563
epinephrine