Chemosensor For Detection Of Zn2 Research Articles

Julolidine-hydrazone based chemosensor for detection of Zn2+: Fluorescent in-situ formed Zn2+ complex discriminates PPi from ADP and ATP

In the present investigation, we have designed and synthesised Zn2+ sensitive Julolidine-hydrazone (JSB) based chemosensor, which crystallised in a monoclinic crystal system with P21/c space group. The bare JSB was nonemissive, but in the presence of Zn2+ ions in solution it showed emission, ascribed to the chelation enhanced emission process, which is also utilised to detect Zn2+ in water samples. Comparing the chromaticity coordinates deduced from the emission colors of the JSB-Zn2+ in solution, powder and hybrid polymer thin film, using CIE (Commission Internationale de I'Eclairage 1931) chromaticity diagram, it was found that compared to the emission of the solution, the emission of the powder was red shifted, while that of the thin film was blue shifted. Further, the sensing of Zn2+ showed reversibility in the presence of pyrophosphate (PPi), which allowed quantification of PPi. Interestingly, in addition to the detection of PPi using the in-situ formed JSB-Zn2+ complex, the process was selective and discriminated PPi from ADP and ATP. The detection of PPi was rationalized via a decomplexation reaction, and translated in the construction of INHIBIT logic gate. Additionally, the possible use of the JSB coated sensor paper for the on-site detection of Zn2+ and subsequent JSB-Zn2+ complex for PPi ions has been demonstrated. The experimental results showed good correlation with the theoretical calculations wherever possible.

A high selective “turn-on” fluorescent chemosensor for detection of Zn2+ in aqueous media

A simple Schiff base fluorescent probe (SW) composed of oxime and salicylaldehyde units was designed and synthesized. The probe has high selectivity and sensitivity for Zn2+ ion in mixed solvent (DMSO/H2O, V/V = 9:1). The fluorescence has obvious redshift phenomenon and visible color change. The stoichiometric ratio of the probe to Zn2+ ion was confirmed to be 1:2 (mole) by 1H NMR, MS analysis and job curves. And the detection limit of fluorescence response of the SW to Zn2+ is down to 2.53 × 10–8 mol/L. At the same time, the probe SW can be applied to the test paper detection of Zn2+ ions under 365 nm UV light and the detection of Zn2+ ions in actual water samples.

A multifunctional aggregation-induced emission (AIE)-active fluorescent chemosensor for detection of Zn2+ and Hg2+

An aggregation-induced emission (AIE)-active fluorescent chemosensor based on a tetraphenylethene (TPE) unit has been successfully designed and synthesized. Interestingly, the luminogen could detect Zn2+ selectively in a THF solution with the detection limit of 1.24 × 10−6 mol L−1. Meanwhile, the luminogen could also detect Hg2+ selectively in a THF-water mixture with the water content of 90%, and the detection limit was 2.55 × 10−9 mol L−1. Furthermore, the solid-state mechanochromic fluorescence behavior of the luminogen was investigated systematically. Indeed, the AIE-active luminogen also exhibited reversible mechanofluorochromic phenomenon involving fluorescent color change from blue to green, and powder X-ray diffraction results indicated that the switchable morphology conversion between crystalline and amorphous states was responsible for this mechanochromism phenomenon.

A novel “off-on” type fluorescent chemosensor for detection of Zn2+ and its zinc complex for “on-off” fluorescent sensing of sulfide in aqueous solution, in vitro and in vivo

We reported a new quinoline-based fluorescent probe 1 for Zn2+ and S2−. 1 showed a highly selective fluorescence enhancement toward Zn2+ over other metal ions including Cd2+, and the resulting 1-Zn2+ complex could detect only S2− among the various anions. The detection limits (0.09 μM and 0.88 μM) for Zn2+ and S2− were much lower than recommended values (76 μM for Zn2+ and 14.8 μM for S2−) by WHO. Their recognition mechanisms were explained by Job plots, UV–vis titrations, 1H NMR titrations, ESI-mass, and theoretical calculations. Moreover, compound 1 with the great photostability and low biotoxicity showed sequentially off-on-off fluorescent bio-imaging of Zn2+ and S2− in both HeLa cells and live zebrafish larvae.

Fluorescent chemosensor for detection of Zn2+ and Cu2+ and its application in molecular logic gate

Abstract In this study, a novel naphthalene schiff-base as a dual-analyte fluorescent sensor for Zn 2+ and Cu 2+ has been designed and synthesized. The sensor shows significant fluorescence enhancement in the presence of Zn 2+ , which might be attributed to inhibit ESIPT process, in contrast, its fluorescence is quenched by Cu 2+ owing to its inherent to the magnetic property. More interestingly, we have successfully utilized the two metal ions (Cu 2+ and Zn 2+ ) as chemical inputs for the manufacture of INHIBIT type logic gate.

A highly selective and sensitive ratiometric fluorescent chemosensor for Zn2+ based on diarylethene with a benzyl-linked 8-aminoquinoline-2-aminomethylpyridine unit

A highly selective and sensitive ratiometric fluorescent sensor for Zn2+ was constructed by using a new diarylethene with a benzyl-linked 8-aminoquinoline-2-aminomethylpyridine unit. Its fluorescence could be reversibly modulated by photoirradiation and metal ions. Stimulated by Zn2+, its emission peak was red-shifted from 421 nm to 515 nm and the emission intensity was enhanced by 7-fold with a concomitant fluorescence color change from dark to bright green. Especially, the diarylethene can effectively avoid interference of Cd2+. Consequently, the diarylethene could serve as a naked-eye fluorescence chemosensor for detection of Zn2+ with high selectivity. The binding stoichiometry between the diarylethene and Zn2+ was 1:1 and the detection limit was 6.6 × 10−8 mol L−1. In addition, a logic circuit was designed on the basis of the unimolecular platform by using the fluorescence intensity at 515 nm as an output and the combinational stimuli of UV/vis and Zn2+/EDTA as inputs.

Three novel input logic gates supported by fluorescence studies: Organic nanoparticles (ONPs) as chemo-sensor for detection of Zn2+ and Al3+ in aqueous medium

Organic nanoparticles (ONPs) of N,N′-ethylenebis(salicylimine) (salen) were synthesized and applied for specific recognition of Zn2+ and Al3+ ions in an aqueous medium. The results show that fluorescence intensity rises with the increasing concentration of Zn2+ in salen solution, proving that salen-ONPs detect Zn2+ efficiently in the aqueous medium as chemo-sensor. Furthermore, the salen-ONPs/Zn2+ system performs as an ON–OFF switch between pH 6.0 and 4.0. Amusingly, although salen-ONPs/Al3+ does not show any significant effect in the fluorescence spectra, highest fluorescence intensity was observed when Al3+ ion was added to salen-ONPs/Zn2+ in a sequential order (addition of Zn2+ to salen-ONPs, followed by Al3+). This system can be applied as a novel three inputs logic gate supported by the fluorescence for the detection of Zn2+ and Al3+ in biological and environmental samples. It appears that photo induced electron transfer (PET) occurs in the salen-ONPs when the fluorophore is excited. For salen/Zn2+ system, the PET is being inhibited considerably by lowering the receptor HOMO energy due to the formation of a bond between the metal ion and ligand, enhancing the fluorescence emission. This is consistent with the theoretical study that the energy of HOMO of the ligand is lower than that of Zn(salen)2+ complex.

A highly sensitive and selective fluorescent chemosensor for detection of Zn2+ based on a Schiff base

A Schiff-base fluorescent probe – 2-((E)-(quinolin-8-ylimino)methyl)quinolin-8-ol (H7L) was synthesized and evaluated as a chemoselective Zn2+ sensor. Upon treatment with Zn2+, the complexation of H7L with Zn2+ resulted in a red shift with a pronounced enhancement in the fluorescence emission intensity in ethanol solution. Moreover, other common alkali, alkaline earth and transition metal ions failed to induce response or minimal spectral changes. Notably, this chemosensor could distinguish clearly Zn2+ from Cd2+. Fluorescence studies on H7L and H7L–Zn2+ complex reveal that the quantum yield strongly increases upon coordination. The stoichiometric ratio and association constant were evaluated using Benesi–Hildebrand relation giving 1:1 stoichiometry. This further corroborated 1:1 complex formation based on Job’s plot analyses. This chemosensor exhibits a very good fluorescence sensing ability to Zn2+ over a wide range of pH.

A Photo-Induced Electron Transfer Based Chemosensor for the Selective Detection of Zn2+ Ions

Aim: The chemosensors permitting naked eye detection of toxic metal ions are user-friendly, portable and obviate the requirement of sophisticated equipments. The objective of the present study was to develop a PET (photoinduced electron transfer) based chemosensor for Zn2+ that changes its color upon binding to Zn2+ allowing naked eye detection. Methods: A new 4-piperazino-1,8-naphthalimide based fluorescent probe 1 was synthesized and its structure was determined using NMR and XRD techniques. The solvatochromic effects on the absorbance and fluorescence characteristics of 1 in aqueous and non-aqueous media were explored. Metal ion competition experiements were performed to monitor the interference of common ions like Li+, Na+, K+, Cu2+, Mg2+, Ca2+, Cr3+, Mn2+, Fe2+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+ and Pb2+. Results and conclusion: The significance of the solvatochromic effect in colorimetric and fluorometric detection of Zn2+, and turn-off sensing of Cu2+ via metal ion displacement have been emphasized. In non-aqueous environment, probe 1 acts as a turn-on chemosensor for Zn2+ and as a turn-off chemosensor towards Cu2+ and thereby, enables the detection of Zn2+ and Cu2+ ions in two different modes. In aqueous environment, the probe 1 acts only as a turn-off chemosensor for Cu2+ ion