Property of cadmium and zinc complex with meso-tetra(3,5-dibromo-4-hydroxyphenyl)porphyrin and simultaneous determination of cadmium and zinc by spectral correction method

The reactions between cadmium(II) and meso-tetra(3,5-dibromo-4-hydroxypheny l)porphyrin (TDBHPP) and zinc(II)- and TDBHPP are both highly sensitive at pH 10. The beta -correction technique has been applied in the simultaneous determination of Cd and Zn instead of the classical spectrophotometry. Two synthetic samples have been determined satisfactorily. Complex properties s tudies comprise the complex ratio, stepwise absorptivity and stability cons tant. id the presence of fluoride and surlfourea, the reaction is selective . The complexes are Cd(TDBHPP) and Zn(TDBHPP), having stability constants 3 .67 x 10(6) and 1.13 x 10(6), real absorptivity 2.25 x 10(5) at 445 nm and 2.24 x 10(5) dm(3) mol(-1) cm(-1) at 435 nm, respectively, and the relataiv e standard deviation is 2.3% for the determination of Cd and 2.2% for that of Zn in synthetic samples.