A ratiometric fluorescent probe for sensitive and selective detection of chromium (VI) in aqueous solutions

A new ratiometric fluorescent probe for sensitive and selective detection of chromium(VI) under acidic conditions using spirolactamized benzothiazole-substituted N,N-diethylrhodol (Cr6P1) was developed. The probe Cr6P1 showed excellent ratiometric selectivity and high sensitivity for Cr(VI) in acidic solutions, and the detection limit for Cr(VI) was as low as 13 nM (6.9 x 10(-4) mg/L). As far as we know, this is the first ratiometric probe based on small organic fluorescence molecules for the detection of Cr(VI). The probe was also applied for detecting Cr(VI) by fluorescent test strips and in the analysis of actual water samples with satisfactory results.