Spectrophotometric Determination of Copper with 6-Hydroxy-5-nitroso 1, 3-dimethyl-1, 2, 3, 4-tetrahydropyrimidine-2, 4-dione

Abstract

Copper (II) was found to react with 6-hydroxy-5-nitroso-1, 3-dimethyl-1, 2, 3, 4-tetrahydropyrimidine-2, 4-dione (HNDU) to form a water-soluble yellow complex easily, and the optimum conditions for the spectrophotometric determination of copper (II) have been studied. The Cu (II)-HNDU complex has an absorption maximum between 420 and 430 nm and shows a definite absorbance over the pH range from 5.5 to 6.8. Beer's law was obeyed up to 10.0 Azglml of copper (II), the molar extinction coefficient of the complex and the sensitivity of the determination being 5.3x 10⁸l/mol cm and 1.2X 10-2 pg Cuicm² for log (I₀/I) = 0.001, respectively. Several ions such as cobalt (II), iron (II), citrate and tartrate interfered with the determination. The molar ratio of copper (II ) to HNDU has been confirmed to be 1: 1 by the mole ratio method.