Sorption–fluorescence determination of aluminum(III) and gallium(III) using immobilized organic reagents

This work reports the development of novel sorption–luminescent methods for the determination of aluminum (Al³⁺) and gallium (Ga³⁺) ions using immobilized organic reagents – morin and Eriochrome Red B. The novelty of the study lies in the integration of solid-phase immobilization with luminescence spectroscopy and quantum-chemical modelling (pKa, pKa*, fluorescence quantum yield analysis, DFT/AM۱), which enabled interpretation of complexation mechanisms and protolytic equilibria. Optimal immobilization conditions on polymeric carriers (pH, contact time, carrier type) were established, ensuring high reagent loading and signal stability. The developed methods achieved detection limits as low as ۰.۰۰۰۶ µg/mL for Al³⁺ and ۰.۰۰۷۸ µg/mL for Ga³⁺, excellent linearity of calibration plots (R² ≥ ۰.۹۹۹), short analysis time (≤۵ minutes), and good repeatability (Sr = ۰.۱۰ and ۰.۰۸). Measurements were performed at pH ۴.۰–۶.۰ (λ = ۵۴۰ nm) for Al³⁺ and pH ۳.۰–۵.۰ (λ = ۶۵۱ nm) for Ga³⁺. Application to natural and industrial wastewater samples demonstrated analytical reliability and practical applicability for routine environmental monitoring. The results highlight the environmental significance of monitoring toxic Al³⁺/Ga³⁺ species and show that the developed reagent–carrier systems can serve as sensitive layers for optical sensor devices, providing a robust and versatile platform for environmental sensing.

کلیدواژه ها:

Aluminum ، Gallium ، Immobilization ، Fluorescence ، Environmental analysis ، Complexation