Novel Fluorescence Signal Magnified Chemosensors for Detection of Fe³⁺ and Hg²⁺ Ions

Abstract

Two novel chemosensors were designed and synthesized, which could detect Fe 3 + and Hg 2 + with high sensitivity. By controlling the molecular ratio of hydrazine hydrate to BODIPY derivatives (OB2), these two different sensors were obtained. The one contains two BODIPY units in each molecule (OS21), the other contains one BODIPY unit in each molecule (OS11). The structures of OS21 and OS11 were studied by 1 H-NMR, Fourier transform infrared spectra (FTIR), and mass spectrometry (MS). The measurements show that OS11 was stable in pH range of 3.65-11.09, while OS21 was stable in pH range of 3.16-11.88. Upon the addition of Fe 3 + and Hg 2 + ions, fluorescence of OS11 and OS21 was quenched notably. Besides, OS21 was more sensitive to both Fe 3 + and Hg 2 + than OS11. And the color of OS11 and OS21 were also changed dramatically with the contacting of Fe 3 + and Hg 2 + . Job's plot indicated that the molar binding ratio of OS11 to Fe 3 + was 1:2, to Hg 2 + was 1:1. The molar binding ratio of OS21 to Fe 3 + was 1:3, to Hg 2 + was 1:1. Also, it is found that the sensor could detect Fe 3 + and Hg 2 + in 0.5 mM concentration. Furthermore, the OS21 shows a fluorescence signal magnification effect as expected comparing with OS11. Moreover, the binding sites in the sensors for Fe 3 + and Hg 2 + ions were investigated as well.

Optical Detection of Fe3+ Ions in Aqueous Solution with High Selectivity and Sensitivity by Using Sulfasalazine Functionalized Microgels

“…Accordingly, one Fe 3+ ion can complex with one or two SSZ moieties, leading to the possible [Fe 3+ ]/[SSZ] ratio of 1 or 0.5, which was consistent with the results obtained from Figure 4B and Figure S7. The binding stoichiometry of SSZ-MGs with Fe 3+ was further determined by Job’s plot [34,35], as shown in Figure 4C. The obtained Job’s plot showed that the A 485nm /A 362nm ratio approached a maximum value when the molar ratio of [Fe 3+ ]/([Fe 3+ ] + [SSZ]) was about 0.44.…”