Ratiometric Detection of Cr³⁺and Hg²⁺by a Naphthalimide-Rhodamine Based Fluorescent Probe

Abstract

Newly synthesized rhodamine derivatives, L(1) and L(2), are found to bind specifically to Hg(2+) or Cr(3+) in presence of large excess of other competing ions with associated changes in their optical and fluorescence spectral behavior. These spectral changes are significant enough in the visible region of the spectrum and thus, allow the visual detection. For L(1), the detection limit is even lower than the permissible [Cr(3+)] or [Hg(2+)] in drinking water as per standard U.S. EPA norms; while the receptor, L2 could be used as a ratiometric sensor for detection of Cr(3+) and Hg(2+) based on the resonance energy transfer (RET) process involving the donor naphthalimide and the acceptor Cr(3+)/Hg(2+)-bound xanthene fragment. Studies reveal that these two reagents could be used for recognition and sensing of Hg(2+)/Cr(3+). Further, confocal laser microscopic studies confirmed that the reagent L(2) could also be used as an imaging probe for detection of uptake of these ions in A431 cells.

Materials for FRET Analysis: Beyond Traditional Dye–Dye Combinations

“…Signal fluctuations can result from variations in local probe concentration, sample thickness, pH, or temperature, which make subsequent interpretation of single-intensity data complicated. Ratiometric FRETbased sensors for the analysis of nucleoside polyphosphates, pH, temperature, hydrogen peroxide (H 2 O 2 ), mercury (Hg), and chromium (Cr) ions have all been demonstrated [79, [86][87][88][89][90].…”

Design of a novel coumarin-based multifunctional fluorescent probe for Zn2+/Cu2+/S2− in aqueous solution

“…However, the simultaneous detection and identification of multiple ions by multifunctional fluorescent probe is still few in number. Compared to single-ion responsive molecular sensors, the multifunctional sensors have been actively developed because of the advantages such as analytical time reduction [27][28][29]. Coumarin is a kind of compound with great fluorescent intensity, high quantum yield, and is very suitable to act as fluorescent chromophores [30][31][32][33].…”

A selective colorimetric and ratiometric fluorescent chemosensor for detection of Al3+ ion

“…However, development of fluorescence ratiometric probes for metal ions has attracted a great deal of attention since they allow the measurement of emission intensities at two different wavelengths. Though many ratiometric chemosensors are reported [14][15][16][17], only a few sensors based on both colorimetric and ratiometric sensing have been reported for detection of Al 3 þ [18][19][20][21][22][23][24][25]. In this work, we designed a ratiometric probe (receptor 1) that displayed a selective colorimetric change and high ratiometric signals toward Al 3 þ among the other examined metal ions.…”