ABSTRACT:
This search includes synthesis of ligand by a two-step, the first react between 4-hydroxy benzaoic acid and thiosemicarbazide to form compound (1) [4-(5-amino-1, 3, 4-thiadiazol-2-yl) phenol], the second step is coupling of diazonium salt [5-(4-hydroxyphenyl)-1, 3, 4-thiadiazole-2-diazonium] with 2-hydroxy-5-sulfobenzoic acid in basic ethanolic media to get compound (2) [(E)-2-hydroxy-3-((5-(4-hydroxyphenyl)-1, 3, 4-thiadiazol-2-yl) diazenyl)-5-sulfobenzoic acid] which characterized by FT-IR ,1H NMR and 13C-NMR , after that used for the spectrophotometric determination of cadmium Cd (II) and lead Pb (II). This method was simple, rapid, sensitive, and selective for reaction between cadmium and lead with the reagent. The maximum absorbance observed at 450 nm and 495 nm for Cd(II) and Pb(II) respectively. The molar absorptivity and sandell’s sensitivity for cadmium (II) and lead (II) complexes are 4.5077×10-4, 2.9709× 104 L.mol-1. cm-1 and 0.0212, 0.0353µg/cm2 respectively. The stability constant of 1:2 [M:L] complexes of Cd(II) and Pb(II) are 3.13 × 105 and 1.45 × 105 L.mol-1 respectively. The linear range of 0.1-9 µg mL-1, 0.2-12 µg mL-1 along with limit of detection 0.059 µg mL-1, 0.102 µg mL-1, relative standard deviation for seven replication measurements (5 µg Cd mL-1 and 5 µg Pb mL-1) of (0.059%) and (0.102%) ,and the recovery range of (98.6) and ( 99.2 ) were obtained for Cd(II) and Pb(II) ions respectively.