Reduced Schiff base as novel two-faced sensor for the detection of iron(III) and carbonate ions

The reduced Schiff base-naphthalene-2-ol (RSB) can be utilized as multifunctional probe to detect both Fe3+ and CO32-. The complexation was formed through coordinate covalent bond between Fe3+ and RSB, and through hydrogen bond between CO32- and RSB. The characterizations were investigated by UV-visible spectroscopy, fluorescence spectroscopy, X-ray photoelectron spectroscopy and confirmed by density functional theory (DFT) calculation. The quenching mechanism of RSB with Fe3+ and CO32- were described through inner filter effect (IFE) and static quenching (SQ), respectively. Furthermore, the quenching of RSB was correlated to the concentrations of Fe3+ (R-2 = 0.9966) and CO32- (R-2 = 0.9954) within a linear range of 1 - 50 ppm. The limit of detection (LOD) and limit of quantification (LOQ) for Fe3+ were determined as 0.75 ppm and 2.52 ppm, respectively. Meanwhile, for CO32-, the LOD and LOQ were 0.27 ppm and 2.73 ppm, respectively. Finally, we demonstrate the application of RSB which can be easily synthesized and obtained with high yield to samples containing Fe3+ and CO32- with concentrations correlated to LOD and LOQ values.