A new rhodamine based OFF–ON fluorescent chemosensors for selective detection of Hg2+ and Al3+ in aqueous media

Abstract

Two novel rhodamine based fluorescent chemosensors (2 and 3) were successfully designed and synthesised which exhibited chromogenic and fluorogenic response to Hg2+ and Al3+ in CH3CN:H2O (1:1, v/v). The detection was not affected by the coexistence of the other common metal ions. The limit of detection (LOD) and association constant (Ka) revealed that the probe 2 has superior binding affinity and sensitivity to Al3+ over Hg2+. Moreover, the probe 3 has superior binding affinity and sensitivity to Hg2+ over Al3+. Binding of ions to the probes 2 and 3 were studied over a wide pH range and the result showed that both the probes can work in physiological pH conditions. Finally, the sensors can be used to detect Hg2+ and Al3+ in tap water samples with a high accuracy.