Flow injection- Spectrophotometeric Determination of some Catecholamine Di ngs in Pharmaceutical Preparations via Oxidative Coupling Reaction with p-ToIuidine and Sodium periodate

A new spectrophotometrie flow injection method lias been established for the determination of some catecholamine drugs [methyl dopn 1, dopaminc.HCl II and adrenaline 111]. The method is based on the oxidative coupling reaction of catecholamine with p-toluidine and sodium periodate to form an orange water-soluble dye product that has a maximum absorption at 480 nni. Linearity was observed in ihe range of 1 -50, 2-50 and 5-70, with a limit of detection (signal/noisc=3) of 0.4, 0.2 and 0.7 pg ml^-1 for 1, II, and 111 respectively. The method was applied successfully to the determination of I, 11 and 111 in pharmaceutical preparations with a good precision and accuracy.