A Rhodamine-Based Sensor for Chromogenic Detection of Cu^(2+) and Fluorescent Detection of Fe^(3+)

摘要

A rhodamine-benzimidazole conjugate(RB) as a probe was investigated.UV-Vis analysis showed that a strong absorption band at 552 nm was formed with the addition of Cu^(2+),while other transition metal ions induced a little more absorption.The absorption value of RB solution at 552 nm has a linear correlation with Cu^(2+) concentration between 35-70 μmol/L;the detection limit reached 6.82×10^(-2) μmol/L,which is lower than the settled limitation for copper in the drinking water(~30 μmol/L) standardized by World Health Organization(WHO).Moreover,FL analysis showed that only Fe^(3+) could induce large fluorescence intensity enhancement at 582 nm;other common metal ions including Cu^(2+) cannot induce the enhancement.There was a good linear correlation between relative fluorescence intensity and Fe^(3+) concentration ranging from 2 μmol/L to 20 μmol/L,and the detection limit reached1.70×10^(-2) μmol/L.The results showed that RB could detect Cu^(2+)and Fe^(3+) simultaneously,with the UV-Vis and fluorescence spectroscopy,respectively.