Novel iron(III) selective fluorescent probe based on synergistic effect of pyrene-triazole units on a cyclotriphosphazene scaffold and its utility in real samples

A novel Fe³⁺ fluorescent probe based on cyclotriphosphazene platform with three pyrene-triazole units at the upper rim as fluoroionophores and three triethylene glycol monomethyl ether units at the lower rim as solubility agents was designed and synthesized for Fe³⁺ ions in mixed aqueous media. The probe exhibited metal-binding ability due to the synergistic effect of among three pyrene-triazole moieties on a cyclotriphosphazene scaffold. The fluorescence emission was significantly quenched by the addition of Fe³⁺ while other added other metal ions and anions induced no spectral changes. The probe sensing conditions such as solvent effects, concentration, competitive metal/anion ions, pH, measurement time and ion binding capability were comprehensively investigated and optimized. The probe was also used for applications in direct determination of Fe³⁺ in real samples including sea water, tap water, industrial waste water and some medicine tablets. Obtained the results were validated with corresponding data from the spike/recovery test and ICP-OES as the standard analysis method. The synthesized probe was found to be highly selective and sensitive for Fe³⁺ with both a limit of detection (0.32 µM) and a limit of quantification (2.88 µM) as being satisfactory when compared with other existing system for the determination of iron ions.