Synthesis, Structural Characterisation, and Sensor Application of a Copper(II)–Glycine Coordination Complex

Abstract

Optical chemical sensors are promising tools for identifying metal ions in a wide variety of samples. Among metal ions, copper (II) has drawn substantial attention due to its toxic properties and its extensive use in numerous industrial processes. In this study, glycine was investigated as a recognition ligand for the optical detection of Cu(II) in aqueous solution. In the Cu (II)–Glycine system, a maximum absorption was observed at 641 nm. The influence of pH on the optical response was examined across a pH range of 2–14. Optical sensing showed excellent linearity between absorbance and the Cu (II) concentration, with correlation coefficients (R2) of 0.9975, along with Cu (II) limits of detection (LOD) of 1 ×10-4 mol dm-3. The sensor system also exhibited outstanding photostability (RSD 0.02 %) and reproducibility under continuous illumination, with negligible interference from common metal ions. Validation with spiked lake water samples confirmed the reliability of the proposed ligand as selective, reproducible, and practical optical sensors for detecting Cu(II) in environmental analyses.