POLAROGRAPHIC-DETERMINATION OF METYROSINE THROUGH TREATMENT WITH NITROUS-ACID

A simple and sensitive polarographic method is described for the deter mination of metyrosine through treatment with nitrous acid. The differ ent experimental parameters affecting the derivatization process, as w ell as the polarographic analysis were studied. The derivatization pro duct was found to be reducible at the dropping mercury electrode over the whole pH range in Britton Robinson buffers. At pH 5, a well-define d diffusion-controlled cathodic wave was produced. The limiting curren t versus the concentration plot was linear over the range 8-80 mumol/l in the direct current mode with a detection limit of 0.2 mumol/l. The method was then applied to the determination of metyrosine capsules, and the results obtained were in good agreement with those given by th e USP method.