We have established methodology for measuring plasma, urine, and cerebrospinal fluid levels of DOPA, DOPAC, and the catecholamine using liquid chromatography with electrochemical detection. One source of contaminating peaks in the assay is dihydrocaffeic acid, a metabolite of caffeic acid, which is a catechol found in coffee. DOPA and DOPAC levels were increased in some patients with pheochromocytoma and in all of 5 patients with neuroblastoma. We currently are developing a liquid chromatographic-radioimmunoassay (LC-RIA) for atrial natriuretic factor.
