Spectrophotometric Determination of Cu2+ with Quinolinyl Derivative in Organic and Aqueous Solutions

Abstract

A spectrophotometric study of complex formation of 4-chloro-2-{[(1E)-quinolin-2-ylmethylene)]amino}phenol (4- Cl-2-QMAP)with copper (II) in aprotic acetonitrile and in protic ethanol and n-butanol has been carried out. The stability constants and stoichiometry of the complexes have been estimated. The stability constant of copper (II)-ligand complex formation grows with growth of solvent polarity/ polarizability and is the greatest in polar aprotic acetonitrile, whereas spectral characteristics of the metal-ligand complex (long-wavelength shift of absorbance maximum, extinction coefficient) grow in H-bond donating solvents-in protic ethanol and n-butanol. 4-Cl-2-QMAP on dioctyl phthalate plasticized PVC film has shown efficient selectivity and sensitivity towards Cu²⁺ in aqueous solution. ortho-Hydroxyphenol quinolinyl derivative on PVC film is found to have higher photostability with respect to same quinolinyl in water and methanol solutions. Embedding of 4-Cl-2-QMAP on PVC is shown to be useful for the spectroscopic determination of Cu²⁺ trace amounts (< 10^-4 M) in aqueous solutions.