A highly sensitive fluorescent 1,8‐naphthalimide Schiff base probe for detection of Hg²⁺

Abstract

A highly sensitive fluorescence “turn‐on” 1,8‐naphthalimide Schiff base probe: N‐allyl‐4‐(ethylenediamine‐salicylidene)‐1,8‐naphthalimide (HL) for Hg2+ was designed, synthesized and characterized. In addition, the sensing behavior of HL towards various transition metal ions has been investigated in solution (DMF/Tris–HCl buffer, 1:1, vol/vol, pH = 7.2). The HL exhibited high selectivity for Hg2+ over other metal ions with obvious fluorescence enhancement. Moreover, the fluorescence intensity of HL showed good linearity with a correlation coefficient (R2) of 0.99, confirming that HL could be applied to detect the quantification of Hg2+ in a linear fashion from 0.5 to 4 μM and the detection limit reach at 0.16 μM. Meanwhile, the association constant (Ka) between Hg2+ and HL achieves 1.23 × 1012 M−1. Moreover, the fluorescence titration experiment and Job plot analysis indicate the formation of a 2:1 stoichiometric complex of HL with Hg2+. The fluorescence enhancement of HL response to Hg2+ ions could be attributed to the photoinduced electron transfer (PET) mechanism.

1,8‐Naphthalimide‐Based Chemosensors: A Promising Strategy for Detection of Metal Ions in Environmental and Biological Systems

“…These results were further supported by DFT studies. In addition, Job's plot revealed 2 : 1 stoichiometric binding between the probe ( 49 ) and metal ion with a detection limit reaching up to 0.16 μM [92] …”

Pyrene‐based ratiometric fluorescent chemosensor for sensitive detection of hypochlorite in a perfect aqueous solution

“…Many analysis methods have been developed to detect ClO À , such as colorimetry, fluorescence, electrophoresis, and electrochemical analysis [13][14][15][16][17][18]. Especially, fluorescence analysis is in the spotlight because of its short response time, high sensitivity, convenience, and low cost [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Among fluorescence analyses, ratiometric fluorescence analysis is most attractive because it uses the ratio between two emission intensities to measure analyte levels, providing built-in corrections for environmental influences and stability [34][35][36][37][38].…”