A solvatochromic-based sensor for chromium(iii) in real systems

Abstract

A very simple, highly sensitive and selective method for the determination of trace amounts of Cr³⁺ in real systems using the solvatochromic properties of a rhodamine-based sensor has been developed. This solvatochromic-based sensor is established using commercially available rhodamine dissolved in different solvents to produce rhodamine lactone (RhoL) via the rhodamine lactone–zwitterion equilibrium. Complexation studies using fluorescence spectroscopy showed that RhoL exhibited the highest colorimetric and fluorescence selectivity and sensitivity to Cr³⁺ in aqueous medium when compared to other metal ions. Importantly, RhoL could directly and rapidly detect Cr³⁺ through filter paper without resorting to additional instrumental analysis.