Simultaneous measurement of urinary and plasma norepinephrine, epinephrine, dopamine, dihydroxyphenylalanine, and dihydroxyphenylacetic acid by coupled-column high-performance liquid chromatography on C8 and C18 stationary phases.

This paper describes a simple and sensitive method for measuring norepinephrine, epinephrine, dopamine, dihydroxyphenylalanine, and dihydroxyphenylacetic acid in urine and plasma. This method involves a two-stage frontal-chromatographic clean-up, followed by coupled minibore high-performance liquid chromatography with electrochemical detection. The use of phenylboronate instead of alumina yields recoveries in the range of 80-90% for all the catecholamines, dihydroxyphenylalanine and dihydroxyphenylacetic acid without interferences. The interassay coefficient of variation for the measurement of these compounds was less than 12%.