Metal ions complexes with an azo compound derived from 2-amino-5-nitrothiazole: spectrophotometric determination and antioxidant activity in spiked samples

Abstract An innovative ligand NTADBrP was employed for the first time in spectrophotometric methods for the simultaneous determination of Fe(III) and Ni(II) ions. Fe(III) and Ni(II) ions were complexed as NTADBrP complexes and the maximum absorption was observed at 615 nm and 642 nm for Fe(III) and Ni(II) respectively. The linear ranges of Beer’s law for Fe(III) and Ni(II) were 2–50 ppm and 1–40 ppm respectively. The molar absorptivity of the complexes was 5.661 × 10 4 L mol −1 cm −1 and 4.707 × 10 4 L mol −1 cm −1 for Fe(III) and Ni(II) respectively. The reproducibility of the method for Fe(III) and Ni(II) showed good precision (RSD = 1.42 % and 1.10 % at 20 ppm) as well as accuracy (recovery = 99.0 %, 98.96 %). For the best concentration of the reagent (3.0 × 10 −4 M), the optimal pH for Fe(III) was 4, and 6 for Ni(II). Various metal ions were tested for their potential interference (Cr 3+ , Cu 2+ , Co 2+ , Hg 2+ , Pb 2+ , and Cd 2+ ) and found effectively masked by suitable masking agents. The method was applied successfully to the determination of iron in pharmaceutical samples using other standard methods for comparison. In addition, significant antioxidant activity against oxidative attack on plasmid DNA showed by NTADBrP.