التقدير الطيفي لايون الكوبلت (II) والنيكل (II) باستخدام الكاشف العضوي 2-](2-كاربوكسي-4-ايودو فنيل ) ازو[-5,4-ثنائي فنيل اميدازول

Abstract

The organic reagent 2-[(2-carboxy-4-iodophenyl)azo]-4,5-diphenyl imidazole (CAPAI) was used for spectrophotometric determination of Co(II) and Ni (II), the reagent has λmax = 443 nm, and it reacts with Co2+ to form a pink complex with λmax = 530 nm at pH = 9.5, while it forms a red complex with Ni2+ of λmax = 511 nm at pH= 10.0. Beer’s law is obeyed in the concentration range (0.005 – 0.06) ppm and (0.005-0.05) ppm for Co(II) and Ni(II), respectively.The molar absorptivity and Sandell’s sensitivity values of Co(II) and Ni(II) complexes were found to be 4.2x104 , 7.3 x 104 l2.mol-1.cm-1 and 0.0014, 0.0008 μg.cm-2 at 530 , 511 nm, respectively. The detection limit was found to be 0.005, 0.003 ppm for Co(II) and Ni(II) respectively. Stability constant, relative standard deviation, relative error and recovery for this spectrophotometer method were estimated for (0.25), (0.15) ppm standard solution of Co(II) and Ni(II) complexes , respectively.The most important interferences were due to , Cu2+, Cd2+ , Zn2+ , Hg2+, Ag+ , Pd2+, were studied , and suitable masking agents were used .This method was applied for the determination of Co(II) and Ni(II) in samples of wastewater of Hilla Textile factory . The results obtained were compared with flame atomic absorption spectrometry method and results are in conformity