A novel fluorescence resonance energy transfer (FRET) system has been designed for the Cu2+ ions detection with optical visual assays. In this FRET reaction, the biocompatible, green luminescent monodisperse phenol formaldehyde resin nanoparticles (PFR NPs) synthesized by a simple hydrothermal method were used as the acceptor and the luminescent CdTe quantum dots (QDs) were selected as the donor. By the layer-by-layer method, the polyelectrolyte (PEI/PSS/PEI) were absorbed alternately on the surface of the PFR NPs. As a result, the amino groups were stably modified onto the surface of the PFR NPs. In the presence of 1-ethyl-3-(3-dimethly aminopropyl) carbodiimide (EDAC) and N-hydroxysuccinimide (NHS), the carboxyl groups coated CdTe QDs prepared by using mereaptoactetic acid (MA) as the stabilizer in water solution were coupled to the surface of amino group functionalized PFR NPs to obtain novel FRET nanocomposites. Owing to the sensitive quenching effect of Cu2+ ions on CdTe QDs and effective energy transfer from CdTe QDs to PFR NPs, the as-prepared FRET nanocomposites were utilized to monitor Cu2+ ion with optical visual detection at room temperature within 1 min. This nanoparticle-based FRET probe should promote further development of other nanocomposites for Cu2+ ion detection in the environmental field.

Phenol Formaldehyde Resin Nanoparticles Loaded with CdTe Quantum Dots: A Fluorescence Resonance Energy Transfer Probe for Optical Visual Detection of Copper(II) Ions

Bioaccumulation describes the ability for microbes or other biological cells to accumulate heavy-metal species from the ambient environment. It has attracted extensive attention in the field of heavy metal remediation and precious metal recovery. Bioaccumulation has also shown great potential for adsorption and preconcentration of ultra-trace levels of heavy metals for their analysis and speciation. Genetic engineering and chemical modification of biological cells open up new avenues for bioaccumulative preconcentration of heavy-metal species for selective analysis and speciation of such metals in combination with spectrometric techniques. We focus on recent progress in genetic and chemical approaches to bioremediation and their applications in selective preconcentration and speciation of heavy-metal species. We also outline the uptake mechanisms of bioaccumulation and key issues in the biosorption of heavy metals and their analysis and speciation. Finally, we discuss future perspectives in the bioaccumulation of heavy-metal species and their analysis and speciation.

Genetic and chemical modification of cells for selective separation and analysis of heavy metals of biological or environmental significance

Core-shell Fe3O4 polydopamine nanoparticles as sorbent for magnetic dispersive solid-phase extraction of copper from food samples.

http://profdoc.um.ac.ir/articles/a/1022416.pdf

Simultaneous extraction and determination of lead, cadmium and copper in rice samples by a new pre-concentration technique: Hollow fiber solid phase microextraction combined with differential pulse anodic stripping voltammetry

A new fluorescent sensor, M201-DPA, based on [5]helicene derivative was utilized as dual-analyte sensor for determination of Cu2+ or Zn2+ in different media and different emission wavelengths. The sensor could provide selective and bifunctional determination of Cu2+ in HEPES buffer containing Triton-X100 and Zn2+ in Tris buffer/methanol without interference from each other and other ions. In HEPES buffer, M201-DPA demonstrated the selective ON–OFF fluorescence quenching at 524 nm toward Cu2+. On the other hand, in Tris buffer/methanol, M201-DPA showed the selective OFF–ON fluorescence enhancement upon the addition of Zn2+, which was specified by the hypsochromic shift at 448 nm. Additionally, M201-DPA showed extremely large Stokes shifts up to ∼150 nm. By controlling the concentration of Zn2+ and Cu2+ in a living cell, the imaging of a HepG2 cellular system was performed, in which the fluorescence of M201-DPA in the blue channel was decreased upon addition of Cu2+ and was enhanced in UV channel upon addit...

Dual-Analyte Fluorescent Sensor Based on [5]Helicene Derivative with Super Large Stokes Shift for the Selective Determinations of Cu2+ or Zn2+ in Buffer Solutions and Its Application in a Living Cell.

Determination of trace copper in food samples by flame atomic absorption spectrometry after solid phase extraction on modified soybean hull

The solid-state reaction method is used to synthesize W-type Sr hexagonal ferrites Sr0.8Pr0.2(Zn1.0−xCox)2Fe16O27 (x = 0.00, 0.15, 0.30, 0.45, 0.60, 0.75). The results of XRD for the W-type hexagonal ferrites, when Co content (x) is 0.00 ≤ x ≤ 0.75, exhibit that they are in the single W-type hexaferrite phase. As shown by morphological analysis, the particles are hexagonal-shaped platelets. The saturation magnetization (Ms) and magneton number (nB) increases with Co content (x) from 0.00 to 0.60. Ms and nB begins to decrease at Co content (x) ≥ 0.60. With increasing Co content (x) from 0.00 to 0.75, the magnetic anisotropy field (Ha), first anisotropy constant (K1), and coercivity (Hc) decrease gradually. The values of DC electrical resistivity for W-type hexagonal ferrites Sr0.8Pr0.2(Zn1.0−xCox)2Fe16O27 (0.00 ≤ x ≤ 0.75) are in the range of 20.854 × 107 Ω-cm and 22.755 × 107 Ω-cm.

/pdf/investigation-into-the-structural-spectral-magnetic-and-e05txqp2.pdf

Yingming Zhang

Papers

Determination of trace copper in food samples by flame atomic absorption spectrometry after solid phase extraction on modified soybean hull

Investigation into the Structural, Spectral, Magnetic, and Electrical Properties of Cobalt-Substituted Strontium W-Type Hexaferrites

Heterogeneous Catalytic Reaction of NO2 to HONO on Hematite