A New Sensing Material Based on Tetraaza/SBA15 for Rapid Detection of Copper(II) Ion in Water

A novel rapid and sensitive optical sensor for Cu(2+) ion detection based on 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium dibromide (TL) immobilized on Santa Barbara Amorphous (SBA-15) has been successfully developed. The inner and outer space of SBA15 allowed a high capacity of TL compound to immobilize onto it. FESEM (Field Emission Scanning Electron Microscopy) analysis was performed to confirm the morphology of TL-SBA15, while FTIR (Fourier Transform Infrared Spectroscopy) was utilized to confirm the interaction of TL–SBA15. A binding study of TL compound towards Cu(2+) ion was performed via UV-vis solution study and binding titration. The stoichiometric binding ratio and binding constant value K(b) of TL towards Cu(2+) ion was 1:1 and 2.33 × 10(3) M(−1), respectively. The optical reflectance sensor based on the TL compound is selective to Cu(2+) ion and demonstrated a linear response over a Cu(2+) ion concentration range of 1 × 10(−7) M to 2 × 10(−5) M, with a detection limit (LOD) of 1.02 × 10(−7) M (R(2) = 0.99) and fast response time of < 1 min. It showed high reproducibility, with a relative standard deviation (RSD) obtained at 0.47%. This optical sensor is reusable up to five consecutive times on Cu(2+) ion by using 0.1 M EDTA with a pH of 6 as a regeneration solution, with a reversibility RSD value of 0.79%. The developed optical sensor provides a rapid and sensitive tool for Cu(2+) ion detection in teabag samples, and the results align with those obtained by the ICP-MS standard method.