a Versatile Schiff Base Chemosensor for the Determination of Trace Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ in the Water and Its Bioimaging Applications

Abstract

In this work, a simple and versatile Schiff base chemosensor (L) was developed for the detection of four adjacent row 4 metal ions (Co2+, Ni2+, Cu2+, and Zn2+) through colorimetric or fluorescent analyses. L could recognize the target ions in solutions containing a wide range of other cations and anions. The recognition mechanisms were verified with a Job’s plot, HR-MS assays, and 1H NMR titration experiments. Then, L was employed to develop colorimetric test strips and TLC plates for Co2+. Meanwhile, L was capable of quantitatively measuring the amount of target ions in tap water and river water samples. Notably, L was used for imaging Zn2+ in HepG2 cells, zebrafish, and tumor-bearing mice, which demonstrated its potential biological applications. Therefore, L can probably serve as a versatile tool for the detection of the target metal ions in environmental and biological applications.

A Simple and Rapid Quinoline Schiff Base as a Fluorescent Probe for Zn2+ and Its Application in Test Strips

“…The corresponding plot of fluorescence intensity versus Zn 2+ concentration was constructed, and a strong linear correlation (Y=‐81.23867+1.0517E8*X, R 2 =0.99591, Figure 3b) was observed over the range of 1~10 μM. Importantly, the remarkable limit of detection (LOD) for Zn 2+ using the rule of 3σ/slope, [40–42] was calculated to be 1.04×10 −7 M compared to the previously published probes [6,26,27,43–59] (Table 1). In addition, the association constant ( K ) for L− Zn 2+ complexation was determined by Benesi‐Hildebrand equation: $${{{{F}_{max}-{F}_{min}}\over{F-{F}_{min}}}={{1}\over{K\left[M\right]}}+1}$$ , [60] to be 3.496×10 4 M −1 (Figure S10), which confirms binding affinity of L towards Zn 2+ .…”

“…Recently, Yuan and his colleagues developed a versatile Schiff base chemosensor for the quantitative detection of trace amounts of Zn 2 + (LOD = 1.09×10 À 7 M) in tap water and river water. [26] The AIEgen chemosensor [(E)-N-(2hydroxybenzylidene)isonicotinohydrazide] is prepared by the condensation of isonicotinic acid and salicylaldehyde, which can selectively detect Zn 2 + ions in a switch mode based on the emission induced by coordination polymerization. [27] Pu et al prepared a novel diarylethene fluorescent probe for the detection of Zn 2 + ions, which showed significant switch emission (λ em = 545 nm, λ ex = 380 nm), accompanied by a fluorescent color change from weak orange to green.…”

“…In the past few decades, a large number of Schiff base chemosensors have been reported in the literature. Recently, Yuan and his colleagues developed a versatile Schiff base chemosensor for the quantitative detection of trace amounts of Zn 2+ (LOD=1.09×10 −7 M) in tap water and river water [26] . The AIEgen chemosensor [( E )‐ N ‐(2‐hydroxybenzylidene)isonicotinohydrazide] is prepared by the condensation of isonicotinic acid and salicylaldehyde, which can selectively detect Zn 2+ ions in a switch mode based on the emission induced by coordination polymerization [27] .…”

A Highly Efficient and Selective Glycine Based Schiff Base Fluorescent Probe for Dual Sensing of Zn(II) and Cu(II) and its Antibacterial Activity and BSA Interaction Studies

“…The nitrogen atom of azomethine moiety (C=N) in Schiff base also exhibits a strong affinity for transition metal ions. [15,16] Schiff base is capable of imparting notable sensing properties along with enhanced stability for specific metal ions owing to the efficient electronic and geometric characteristics of the host-guest complexation. [17] The presence of binding sites viz., N and O in the salicylaldimine based Schiff base enable the probe to bind to the metal ions efficiently resulting into turn-on and turn-off florescence revealing selectivity to particular ions.…”

Dual-Mode Multiple Ion Sensing via Analyte-Specific Modulation of Keto–Enol Tautomerization of an ESIPT Active Pyrene Derivative: Experimental Findings and Computational Rationalization

“…Copper toxicity causes oxidative stress and related symptoms, leading to diabetes and neurodegenerative disorders such as Alzheimer’s, Parkinson’s, Menkes, and Wilson’s diseases . However, despite a considerable number of optical probes reported in the literature for simultaneous detection of both Zn 2+ and Cu 2+ ions, − there is still a demand for new colorimetric probes that can make distinguishable “naked-eye” detection in the visible-wavelength region. This is particularly fascinating as it does not involve sophisticated instruments or skilled technicians for execution.…”