A New Pyrrole-2-carboxaldehyde Functionalized Chitosan-Cu(II) Complex-based Chemosensor for Iodide Anion in Aqueous Media

Iodine is an essential ingredient in thyroid hormones of which both low and high intakes may cause thyroid disease. This study develops a Pyrrole-2-Carboxaldehyde functionalized chitosan-Cu(II) Complex [PCAFC-Cu(II)] chemosensor, for quick and easy detection of iodide ions from its aqueous solutions. PCAFC-Cu(II) complex was synthesized from a simple condensation reaction of chitosan (CS) and pyrrole-2-carboxaldehyde (PCA) along with an aqueous solution of copper(II) salt. The starting materials and the products were characterized by spectroscopic (FT-IR and UV-Visible), X-ray powder diffraction, and microscopic methods (Scanning Electron Microscopy). The PCAFC-Cu(II) colorimetric sensing of I- revealed a color change adduced to the formation of a hydrogen bond or deprotonation of the complex matrix. Colorimetric detection for I- ions was obtained with a detection limit (LoD) of 0.005 M and the complex has high specificity for I- ions detection from a solution consisting of several anions. The synthesized complex [PCAFC-Cu(II)] could serve as an on-site reagent for the qualitative detection of iodide ions.