Rapid, sensitive, and selective copper (II) determination using sensitive chromogenic azo dye based on sulfonamide

Area of Science:

• Analytical Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Accurate determination of copper(II) ions is crucial in various environmental and biological applications.
• Existing methods for copper detection may lack sensitivity, selectivity, or simplicity.
• Development of novel analytical tools for metal ion quantification remains an active research area.

Purpose of the Study:

• To develop simple, sensitive, and selective methods for Cu(II) ion determination in aqueous solutions.
• To synthesize and characterize a novel azo dye ligand and its metal complexes.
• To create a Cu(II)-selective potentiometric sensor based on the synthesized ligand.

Main Methods:

• Spectrophotometric determination of Cu(II) using an azo dye ligand (H2L) at pH 10.0.
• Development of a poly(vinyl chloride) membrane-based potentiometric sensor incorporating the azo dye as an ionophore.
• Synthesis and structural characterization of Cu(II), Co(II), and Ni(II) complexes with the azo dye ligand.

Main Results:

• The spectrophotometric method showed a linear relationship between absorbance and Cu(II) concentration (R² = 0.9992) with a detection limit of 1.1 × 10⁻⁷ mol L⁻¹.
• The potentiometric sensor exhibited a Nernnian response for Cu(II) over a wide concentration range (1.0 × 10⁻⁶–1.0 × 10⁻² mol L⁻¹) with good selectivity.
• Isolated Cu(II) complex displayed a square planar geometry, while Co(II) and Ni(II) complexes showed tetrahedral geometries.

Conclusions:

• The developed spectrophotometric and potentiometric methods are simple, selective, and highly sensitive for Cu(II) determination.
• The novel azo dye ligand effectively functions as a chromogenic reagent and an ionophore for Cu(II) sensing.
• The synthesized metal complexes provide insights into coordination chemistry and potential applications.