Monitoring Of Cu2 Research Articles

Monitoring of Cu2+ release from controllably synthesized nano-copper pesticides

ABSTRACT Copper-based nanopesticides hold significant promise for agricultural applications. However, a critical challenge that persists is the need for effective control over the release of Cu2+. To this end, this study systematically investigated the Cu2+ release characteristics of Cu-based NPs with varying morphologies, species, and coating agents. It is found that CuO NPs exhibited extremely low Cu2+ concentration, rendering them ineffective for plant disease control. Cu(OH)2 nanowires cannot continuously release Cu2+ due to its larger size and enhanced stability. Conversely, Cu(OH)2 NPs exhibited sustained Cu2+ release, albeit at a slower rate. Modification with surfactants could significantly affect the Cu2+ release behavior, particularly the coating of carboxymethyl starch, which notably promoted Cu2+ release from Cu(OH)2 NPs, achieving sustained release for 27 days. Furthermore, carboxymethyl starch-coated Cu(OH)2 particles could consistently release Cu2+ in the pH range of 5–7. This finding may offer the inspiration of long-lasting control of plant diseases.

Chelation therapy-inspired design of a water-stable fluorescent probe for the effectual monitoring of copper(II) ions in real water.

This work introduces a thought-provoking design to develop a water-soluble chemical probe, sodium 4-hydroxy-3-((E)-((E)-((2-hydroxynaphthalen-1yl)methylene)hydrazono)methyl) benzenesulfonate (SW2) and its analytical characterization for the efficient detection and monitoring of Cu2+ ions in a matrix of s-, d-, and f-metal ions in pure water. The water-stable molecular probe, SW2, in the presence of Cu2+ salts in pure water exhibits a fluorescence turn-off characteristic with a high detection limit, 3.8 μM, and irresistibly holds 4-cycle reversibility in the presence of sulphide ions without any significant loss of its chemosensing efficiency. Spectroscopic and computational studies ensure 1 : 1 complexation between SW2 and Cu2+ ions, leading to the formation of SW2-Cu2+ chelate, thus inducing dynamic quenching of SW2 emission, which subsequently reverts on the addition of S2- ions in water. Additionally, the SW2-Cu2+ chelate was isolated in microcrystalline powder and the complexation was studied with mass spectrometry and EPR analysis. Computational analysis reveals the remarkable reduction in the S0-S1 energy level of the SW2-Cu2+ complex, which is attributed to the drastic quenching of the fluorescence intensity. Furthermore, SW2 was successfully applied to the detection of Cu2+ ions in tap and pond water. Interestingly, the probe is also effective for the determination of Cu2+ ions in the aqueous solution of a Cu-based fungicide (copper oxychloride), commercially available as Blitox in India, thus evaluating the effectiveness of SW2 in real sample analysis.

Polyadenine-based fluorescent probe for high-selective determination of copper ion in freshwater

ABSTRACT In this work, a polyadenine-based fluorescent probe (pAFP) was designed for highly selective determination of Cu2+ in various freshwater sources. The pAFP contained a fluorescent group carboxyfluorescein (FAM) and a guanine-cytosine-guanine-cytosine (GCGC) sequence which was linked to the ends of a polyadenine strand. The complexation between polyadenine strand and Cu2+ induced the transition of polyadenine strand from a loose random coil to a compact structure, resulting in the proximity of the GCGC to the FAM and subsequent fluorescent quench of the FAM. Our work identified the polyadenine strand as a novel recognization element for Cu2+, which displayed high selectivity and appropriate affinity (104 ~ 105 M−1) to Cu2+, with a stoichiometric ratio of 1:1. Based on it, the pAFP provided a dynamic range from 80 nM to 20 µM for the determination of Cu2+and a detection limit of 62 nM, meeting the requirements of the World Health Organization (WHO) and Environmental Protection Agency (EPA). The analysis of Cu2+-spiked real samples from lentic (Yudai Lake) and a lotic freshwater system (Xiangjiang River) revealed the high accuracy of the method, evidencing the application of this proposed sensor towards wide-field freshwater detection. Compared to other reported fluorescent probes, our pAFP displays a much simpler composition and structure. Meanwhile, in the actual procedure, our method only requires a simple pretreatment of the water sample by a 0.22 μm syringe filter, and the whole test procedure can be completed within 10 min. Such a convenient, low-cost and time-saving method for the determination of Cu2+will greatly facilitates the on-site and real-time monitoring of Cu2+ in different freshwater sources and subsequent water quality control.

A sequential logic gate-based "smart probe" for selective monitoring of Cu(2+), Fe(3+) and CN(-)/F(-)via differential analyses.

A sequential logic gate-based probe has been constructed for the detection of Cu(2+), Fe(3+), CN(-) and F(-) at ppm levels which potentially meets real-world-challenges through a simple synthetic route, with rapid response, water based-activity, visualization by the naked eye, regenerative action, high selectivity and multiple readout for precise analysis.

A coumarin-derived fluorescent chemosensor for selectively detecting Cu2+: Synthesis, DFT calculations and cell imaging applications

A novel coumarin-based fluorescent probe L ((4E)-4-((7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl) methyleneamino)-1,2-dihyydro-2,3-dimethyl-1-phenylpyrazol-5-one) has been developed as a simple and efficient chemosensor which exhibits a significant fluorescence reduction in the presence of metal cations. This sensor exhibits high selectivity and sensitivity toward Cu2+ over other common cations. The mechanism for detecting copper was evaluated by time-dependent density functional theory (TD-DFT) calculations and the coordination mode was also confirmed by density functional theory (DFT) calculations. Furthermore, results of cell imaging in this study indicate that this new probe may be useful for detection and monitoring of Cu2+ in biological applications.

Fluorescence turn-on chemodosimeter-functionalized mesoporous silica nanoparticles and their application in cell imaging

The monitoring of Cu2+ levels in living cells has attracted increasing interest, however, the techniques used often suffer from interference from Hg2+. In the present study, we synthesized mesoporous silica nanospheres modified with a rhodamine B derivative containing a thiourea group to be used as a chemodosimeter-functionalized nanoprobe for the detection of Cu2+. This system is expected to offer selective detection of Cu2+ over Hg2+, as these ions react differently with the rhodamine derivative. This chemodosimeter-functionalized nanoprobe was characterized by transmission electron microscopy, small-angle X-ray diffraction, and N2 adsorption–desorption isotherms. The nanoprobe's response to metal cations was investigated using absorption and fluorescence spectroscopies. Addition of Hg2+ or Cu2+ induced a significant solution color change (colorless to purple) and an enhancement in fluorescence of the nanoprobe, even in the presence of other cations in aqueous media. Cu2+-promoted ring-opening and hydrolysis of rhodamine led to the release of rhodamine from the mesoporous nanospheres, while this reaction is not observed in the presence of Hg2+, allowing effective discrimination of these ions through a simple centrifugation treatment. The living cell imaging experiments further demonstrate its value in bioimaging intracellular Cu2+ by virtue of its water solubility, membrane permeability, and nontoxic nature.