Determination Of Copper Ions (II) Using The Reagent 4-[(4-Amino-3-Hydroxyphenyl) Diazenyl]-3-Hydroxynaphthalene-1-Sulfonic Acid By Spectrophotometric Method

Abstract

Copper (II) was determined using the reagent 4-[(4-amino-3-hydroxyphenyl)diazenyl]-3-hydroxynaphthalene-1-sulfonic acid in its aqueous solutions by the spectrophotometric colorimetric method, by formation of a greenish-yellow colored complex in the presence of a Britton buffer at pH 8. The experimental study showed that the maximum absorption wavelength of the formed complex is 440 nm, and the reaction ratio between the reagent and copper (II) was (2:1), while the maximum value of the molar absorptivity coefficient and the complex formation constant were ε = 1.07×10⁴ L.mol⁻¹.cm⁻¹ and β = 8.91×10³ respectively. All factors affecting the copper-reagent complex formation process were studied, where linearity was occurred within the concentration range (0.2-6) mg/L, with a detection limit of 0.04 mg/L and a Sandell sensitivity of 0.01 μg/cm². The relative standard deviation values ranged within (0.95-4.23)%, and the recovery ranged within (95-102.5)% when this method was applied to standard copper samples, indicating the validity and accuracy of the method and the possibility of using the reagent to determine copper (II).