A novel rhodamine-based colorimetric and fluorescent sensor for the dual-channel detection of Cu~(2+) and Fe~(3+) in aqueous solutions

摘要

A novel xanthene dye was designed and synthesized from rhodamine B, hydrazine hydrate and 4-chloro-7-nitro-2,1,3-benzoxadiazole. The sensing activity of the new rhodamine dye toward metal ions was carefully investigated. In H2O/CH3CN (1/1, v/v), the dye showed high selectivity and sensitivity to Cu~(2+) by remarkable absorption and fluorescence enhancement, while in H2O/CH3CN (99/1, v/v), the dye behaved as a high selective and sensitive turn-on fluorescent sensor for Fe~(3+). The detection was essentially insensitive to H~+ concentration between pH 2.6 and 10.9. The sensing mechanism was explored by IR and LC—mass spectroscopic techniques and the LC—mass analysis results indicated that a 1:1 complex was formed between Cu~(2+) (or Fe~(3+)) and the sensor.