Optical copper(II) sensor based on immobilised salicylic acid in sol-gel film and fluorescence quenching measurement

An optical copper (II) sensor has been developed in this study by applying immobilized salicylic acid in sol gel film as reagent phase, based on fluorescence quenching measurement. It has been known that copper displays important role in enzymatic metabolism in the human body. Promising results were achieved under optimum pH 5.0, when the fluorescent signal was measured at excitation and emission wavelengths of 350 nm and 440 nm, respectively. The linearity was found in the Cu(II) concentration range of 5.0 - 80.0 /spl times/ 10/sup -6/ M with LOD of 4.4 /spl times/ 10/sup -6/ M. Nine repetitive measurements yielded good repeatability (3.49 % RSD) and reproducibility (7.25 % RSD). Intramolecular photoautomerism of salicylic acid related to thermodynamic reaction observed in this study showed another important feature in chemical sensing.