Visual Detection Of Cu2 Research Articles

Sensitive Naked Eye and Autofluorescence Detection of Cu(2+) in Biological Fluids by Polyethyleneimine Microspheres.

In this paper, an autofluorencent polyethyleneimine (PEI) microspheres probe has been designed as the two channel sensor for both quantitative fluorescence and visual detection of Cu(2+). We synthesized autofluorescent microspheres crosslinked with glutaraldehyde by controlling volume ratio between oil phase and water phase. A novel fluorescent platform for sensing Cu(2+) based on the autofluorescence quenching of PEI microspheres by Cu(2+) with a detection limit as low as 2nM. In addition, the absorbance of PEI microspheres at 205nm, 325nm, 590nm and 800nm were sensitive to the presence of Cu(2+). The strong chelation interaction between Cu(2+) and -NH2 on the surface of microspheres produced the fluorescence quenching and color change of PEI microspheres which facilitated our sensing approach. We regard the developing of autofluorcent PEI microspheres as the dual-channel sensor for Cu(2+) would provide autofluorcent microspheres a future application in quantitative analysis.

Colorimetric determination of Cu(II) ions in biological samples using metal-organic framework as scaffold

In this paper we developed a novel optical chemo-sensor for visual detection of Cu(II) ions in the water and biological samples. DDTC/UiO-66 sensor is based on the use of metal-organic frameworks (UiO-66) with its high surface area, morphology and shape in order to obtain a highly sensitive chemo-sensor. Using the designed sensor the naked eye can detect the ultra-trace of Cu(II) ions in a simple, fast, inexpensive way, which is considered the main demand on the new technologies. Calibration curves were constructed by using two techniques UV–vis Spectrophotometric and Digital Image-based Colorimetric analysis. In the two techniques, the developed chemo-sensor has a wide range of Cu(II) ion detection up to10−9mol/L with a very fast response time. DDTC/UiO-66 sensor can be used to determine the concentration of Cu(II) ions in water and biological samples like blood and serum with very effective results.

Ratiometric fluorescent paper sensor utilizing hybrid carbon dots-quantum dots for the visual determination of copper ions.

A simple and effective ratiometric fluorescence nanosensor for the selective detection of Cu(2+) has been developed by covalently connecting the carboxyl-modified red fluorescent cadmium telluride (CdTe) quantum dots (QDs) to the amino-functionalized blue fluorescent carbon nanodots (CDs). The sensor exhibits the dual-emissions peaked at 437 and 654 nm, under a single excitation wavelength of 340 nm. The red fluorescence can be selectively quenched by Cu(2+), while the blue fluorescence is a internal reference, resulting in a distinguishable fluorescence color change from pink to blue under a UV lamp. The detection limit of this highly sensitive ratiometric probe is as low as 0.36 nM, which is lower than the U.S. Environmental Protection Agency (EPA) defined limit (20 μM). Moreover, a paper-based sensor has been prepared by printing the hybrid carbon dots-quantum dots probe on a microporous membrane, which provides a convenient and simple approach for the visual detection of Cu(2+). Therefore, the as-synthesized probe shows great potential application for the determination of Cu(2+) in real samples.

Fluorescent paper sensor fabricated by carbazole-based probes for dual visual detection of Cu2+and gaseous H2S

Cyclically detect Cu2+–S2−and visual detections of Cu2+–H2S with sensor papers fabricated by carbazole-based fluorescence probe.

A highly selective quinaldine–indole based spiropyran with intramolecular H-bonding for visual detection of Cu(II) ions

A novel quinaldine–indole based spiropyran (QSP) with stabilized merocyanine form has been developed for colorimetric detection of Cu2+ ions. Chemosensor QSP shows high sensitivity and selectivity for Cu2+ ions amongst other metal ions (Na+, Mg2+, K+, Ca2+, Al3+, Co2+, Ni2+, Zn2+, Cd2+, Ba2+, La3+, Hg2+, Pb2+). The stoichiometry of QSP-Cu2+ complex determined by Jobs plot was found to be 1:1. The association constant for QSP-Cu2+ complex determine from Benesi–Hildbrand plot was 1.9×105M−1 with a limit of detection 6.3×10−7M. Applicability of QSP to detect Cu2+ ions in tap water has been demonstrated, thus indicating the potential use of QSP as viable probe for visual detection of Cu2+ ions.

Copper ion-induced fluorescence band shift of CdTe quantum dots: a highly specific strategy for visual detection of Cu(2+) with a portable UV lamp.

We have developed a new colorimetric strategy that allows visual detection of Cu(2+) under the irradiation of a UV lamp with high specificity based on the phenomenon that copper ions may lead to a fluorescence band shift of CdTe quantum dots (QDs) while other concomitant ions will not.

Colorimetric detection and removal of copper(II) ions from wastewater samples using tailor-made composite adsorbent

The nitrogen donor ligand was functionalized with polarable mesoporous silica as composite adsorbent, by a cost-effective and environmentally friendly procedure, for highly selective copper (Cu(II)) ions detection and removal from water. The nitrogen donor ligand of N,N(octane-1,8-diylidene)di(2-hydroxy-3,5-dimethylaniline) was synthesized to be specific to Cu(II) ions. The composite adsorbent permitted fast and specific Cu(II) ions capturing via colorimetric naked-eye detection based on stable complexation [Cu(II)–ligand]n+ mechanism. The effect of pH value, interferential metal ions, initial Cu(II) concentration, and contact time on adsorption capability were investigated systematically. The adsorbent was selective toward Cu(II) as shown by a light yellow to green color change. This was characterized by UV–vis spectroscopy and the color change was observed for the visual detection of Cu(II) ions. The ions selectivity of the adsorbent toward Cu(II) was determined by changes in UV–vis reflectance spectra. However, the presence of competing ions showed no interference for the detection of Cu(II) ion by the composite adsorbent. The results demonstrated that the composite adsorbent exhibited excellent sorption performance for Cu(II) ions. The low detection limit and sorption capacity of the adsorbent were 0.10μg/L and 200.80mg/g, respectively. The adsorbed Cu(II) was eluted with suitable eluent and simultaneously regenerated into the initial form for next operation without significant deterioration in its nanostructure case cavities. The data also confirmed that the adsorbent is a cost-effective and environmentally friendly procedure for Cu(II) treatment. Therefore, the composite adsorbent can be considered as a potential adsorbent for Cu(II) ions monitoring and removal from wastewater.

Highly Sensitive Visual Detection of Copper Ions Based on the Shape-Dependent LSPR Spectroscopy of Gold Nanorods

We have developed a novel approach to the rapid visual detection of Cu(2+) in natural samples based on the copper-mediated leaching of gold nanorods (GNRs). In the presence of hexadecyltrimethylammonium bromide, which can reduce the redox potential of Au(I)/Au, the GNRs are catalytically etched by Cu(2+) preferentially along the longitudinal direction. And as a result, the localized surface plasmon resonance extinction peak shifts to short wavelength, accompanied by a color change from blue to red. The leaching mechanism has been carefully discussed in a series of control experiments. Under optimal conditions, this sensor exhibits good sensitivity (LOD = 0.5 nM). Most importantly, the approach is highlighted by its high selectivity for and tolerance of interference, which enables the sensor to detect Cu(2+) directly in a complex matrix, especially in seawater. Moreover, such a nanoparticle-based sensor is also successfully applied to test paper for the visual detection of Cu(2+).

Ion-induced cycle opening of a diarylethene and its application on visual detection of Cu2+ and Hg2+ and keypad lock

Only the closed form of the diarylethene reported here can combine with the metal ions, meanwhile the coordination would surprisingly induce cycle opening of photochromic unit and color bleaching process. These properties can be applied in detection of Cu2+ and Hg2+ ions and single molecular keypad lock.

Visual detection of Cu(ii) ions based on a simple pyrene derivative using click chemistry

A ratiometric fluorescent probe for the visual detection of Cu2+in aqueous media has been developed based on a “click” reaction between a pyrene azide and a positively charged terminal alkyne.

A pyridoxal-based dual chemosensor for visual detection of copper ion and ratiometric fluorescent detection of zinc ion

A pyridoxal-based fluorescein derivative was synthesized by reacting fluorescein hydrazide and pyridoxal hydrochloride in ethanol and characterized by NMR, ESI-MS and X-ray. The optical properties of probe were investigated in methanol: HEPES solution. The probe displayed selectivity for Cu2+, which was characterized using UV–visible spectroscopy. Moreover, the process also allowed visual detection of Cu2+ by a colorless to yellow change. In contrast, selectivity toward Zn2+ was determined in the emission spectra showing OFF–ON type fluorescence changes from colorless to green. This represents the first reported pyridoxal-based sensor capable of detecting both Cu2+ and Zn2+ using two different modes. Furthermore, it can be used to bioimaging.

A Rhodamine-Cyclen Conjugate as Chromogenic and Fluorescent Chemosensor for Copper Ion in Aqueous Media

A novel compound 1 containing rhodamine B and macrocyclic groups has been synthesized. It was found to exhibit a reversible colorimetric response, high selectivity and sensitivity for Cu(II) ion over other commonly coexistent metal ions. The colorimetric and fluorescent response to Cu(II) can be conveniently detected even by the naked eye, which provided a facile method for visual detection of Cu(II). Approximate 71 and 53-fold enhancement in the absorbance at about 557 nm and fluorescence intensity at about 580 nm were estimated when Cu(II) ion was added to the aqueous media of compound 1. The detection limit was calculated to be 2 μM.

DNAzyme crosslinked hydrogel: a new platform for visual detection of metal ions

We propose the use of DNAzyme as a crosslinker of hydrogel to develop a catalytic platform for the sensing of metal ions. The DNAzyme crosslinked hydrogel can undergo gel-sol transition in response to Cu(2+) ions, which enables sensitive visual detection of Cu(2+) by observing the release of pre-trapped AuNPs.

A rhodamine-based dual chemosensor for the visual detection of copper and the ratiometric fluorescent detection of vanadium

The optical properties of a novel, rhodamine-based derivative, synthesized by reacting rhodamine hydrazide and 5-chlorosalicylaldehyde in ethanol, were investigated in methanol:HEPES solution. The novel sensor displayed selectivity for Cu2+, as evidenced by a colourless to dark red colour change, which was characterized using UV–visible spectroscopy and which also allowed visual detection of Cu2+. In contrast, selectivity towards VO2+ was determined from changes in the emission spectra in the nanomolar range. This represents the first reported rhodamine-based sensor capable of detecting both Cu2+ and VO2+ using two different modes.

A diamide–diamine based Cu 2+ chromogenic sensor for highly selective visual and spectrophotometric detection

A diamide–diamine based sensor 3 possessing anthracene-9,10-dione as a chromogenic moiety has been synthesized and demonstrates a highly selective colour change from red to blue with Cu 2+ for visual detection of Cu 2+ (5–50 μM). Other metal ions, viz. Fe 2+, Cr 3+, Co 2+, Ni 2+, Zn 2+, Cd 2+, Ag +, Pb 2+, Na +, K +, Mg 2+, Ca 2+, Sr 2+ and Ba 2+ cations do not lead to any change in colour and their presence does not interfere with the visual and quantitative analysis of Cu 2+. The selective deprotonation of an aryl amine NH by Cu 2+ is responsible for a bathochromic shift and significant colour changes. Significantly, the stability of the 3·Cu 2+ complex between pH 7 and 12 allows Cu 2+ estimation under neutral and basic conditions.