Abstract
An effective Hg2+-specific probe1was designed and prepared based on Phthalimido Gly modified rhodamine B. The sensing behavior of probe1was studied by UV-Vis and fluorescence spectroscopy. Probe1showed excellent high selectivity and sensitivity towards Hg2+over commonly coexistent metal ions in neutral solution, which could be attributed to the Hg2+-triggered ring opening of the spirolactam of the rhodamine moiety and the formation of a 1 : 11-Hg2+complex. The limit of detection (LOD) based on3δblank/kwas calculated to be 2.8 × 10−8 M, as well as an excellent linear relationship with the concentration of Hg2+in the range from 0.1 × 10−6to 1.0 × 10−6 mol/L (R2=0.98927). In addition, the effects of pH, coexisting metal ions, and the reversibility were investigated in detail.
Highlights
E design and development of uorescent chemosensors for detection of environmentally and biologically important metal cations are currently of signi cant importance [1,2,3,4,5]
Rhodamine B and its derivatives are a kind of excellent candidate for the construction of an off/on-type uorescent chemosensor and well known for their desirable properties, including excellent spectroscopic properties, high extinction coefficient (>75,000 cm−1 M−1), high uorescence quantum yield, long absorption and emission wavelength elongated to the visible region [15,16,17,18]. e mechanism is based on the switch “offon” of the spirocyclic moiety mediated by guest
On binding guest to the receptor, the spirocyclic form of rhodamine B which is colorless and non uorescent, whereas ring opening of the corresponding spirolactam induced by metal ions gives rise to strong uorescence emission and a pink color [19,20,21,22]
Summary
E design and development of uorescent chemosensors for detection of environmentally and biologically important metal cations (such as Hg2+, Fe3+, and Al3+) are currently of signi cant importance [1,2,3,4,5]. Current techniques for Hg2+ screening, uorescence chemosensors offer a nondestructive and prompt detection of Hg2+ by a simple uorescence enhancement (turn-on) or quenching (turn-off) response in biological, toxicological, and environmental monitoring, due to its simplicity and distinct advantages in sensitivity and selectivity to recognition of Hg2+ [9,10,11,12,13,14]. N(Et) probe 1 exhibited prominent absorption and uorescence enhancements to Hg2+ ions with a particular selectivity and excellent sensitivity and could be used for naked-eye detection
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