A rhodamine-based novel turn on trivalent ions sensor

In this study, a new rhodamine derivative (Rhodamine dipyridyl (the probe RDP)) was synthesized for trivalent ions selectivity based on colorimetric and fluorometric detection. The effects of different metal ions such as Li+, Na+, K+, Ag+,Mg2+, Ca2+, Ba2+, Cd2+, Zn2+, Cu2+, Hg2+, Pb2+, Fe2+, Mn2+, Co2+, Fe3+, Cr3+, and Al3+ on the photo-physical properties of the probe RDP were investigated in water/ethanol (1:1, v/v). According to the data obtained, a new peak at 560 nm in the absorption spectrum of the probe RDP and an increase in fluorescence intensity of its were observed in the presence of Fe3+, Cr3+, and Al3+ (M3+) ions. The binding constants were calculated using the Benesi-Hildebrand equation and found to be 1.42 x 10(3) M-1 for Fe3+, 3.88 x 10(3) M-1 for Al3+ and 9.16 x 10(3) M-1 for Cr3+. The limit of detection (LOD) values were found to be 1.17 mu M for Al3+, 2.50 mu M for Fe3+ and 3.16 mu M for Cr3+. The interaction ratio between the probe RDP and M3+ ions was determined as 1:2. Also, the response times of the probe RDP were less than 1 min for trivalent ions.