Preparation and Analytical Studying of Ligand (NO2BTAHB) with (Cu) - Ion

In this study, organic reagent 2-[6-Nitro-2-benzothiazolylazo]-4-hydroxy benzoic acid (NO₂BTAHB) was synthesized. A sensitive and selective spectrophotometric method was proposed for the rapid determination of Cu(II) using (NO₂BTAHB) reagent. The reaction between Cu(II) and (NO₂BTAHB) reagent is instantaneous at pH=6.0 and the absorbance remains stable for over 24 hrs.

The Method allows for the determination of Cu(II) over the range (0.1-6.0) μg.ml^-1, with molar absorptivity of (7.45 x 10⁺³)l.mol^-1.cm^-1 and a detection limit of 0.0245 μg.ml^-1. Recovery and relative error values of precision and accuracy of method were found to be R.S.D=1.7% , Re=98.6% , and Erel=-1.4%. The properties of complex was studied and show; (M:R) ratio was 1:2 at pH=6.0 ,and the stability constant of 7.796 x 10⁺⁹L².mol^-2. The interferences of ions (Ni²⁺, CrO^2-, Ca²⁺, pb²⁺, Cu⁺², WO₄^-2, MO₄^-2, Co²⁺, Mg²⁺, Cd²⁺, Ba²⁺, Bi³⁺) and masking agents effect on absorbance were studied.