Abstract: A method of third derivative spectrophotometric simultaneous determination ofmicro amount of copper,cobalt and cadmium with meso-tetrakis[4-(trimethylammonium)phenyl]porphine has been established.The absorption maxima of the third derivative spectrafor copper,cobalt and cadmium complexes were localed at 412nm,434nm,438nm,respec-tively,They could be used for simultaneous determinatlon of copper,cobalt and cadmium.The molar absorptivities of third derivative spectra were 1.11?10 ⁶(Cu),3.95?10 ⁵(Co)and 6.47?10⁵(Cd)L· mol^-1· cm^-1,respectively,The method has been used to determine syn-thetic mixtures of copper,cobalt and cadmium,and satisfactory results were obtained withrelative errors<4%.

Key words: copper, cobalt, cadmium, simultaneous determination, derivative spectropho-tometry, meso-tetrakis[trimethylammonium phenyl]porphine