Detection Of Cobalt Ions Research Articles

A Semi-Automatic Environmental Monitoring Device for Mercury and Cobalt Ion Detection.

A syringe-based, semi-automatic environmental monitoring device is developed for on-site detection of harmful heavy metal ions in water. This portable device consists of a spring-embedded syringe and a polydimethylsiloxane (PDMS) membrane-based flow regulator for semi-automatic fix-and-release fluidic valve actuation, and a paper-based analytical device (PAD) with two kinds of gold nanoclusters (AuNCs) for sensitive Hg2+ and Co2+ ion detection, respectively. The thickness of the elastic PDMS membrane can be adjusted to stabilize and modulate the flow rates generated by the pushing force provided by the spring attached to the plunger. Also, different spring constants can drastically alter the response time. People of all ages can extract the fix-volume sample solutions and then release them to automatically complete the detection process, ensuring high reliability and repeatability. The PAD comprises two layers of modified paper, and each layer is immobilized with bovine serum albumin-capped gold nanoclusters (R-AuNCs) and glutathione-capped gold clusters (G-AuNCs), respectively. The ligands functionalized on the surface of the AuNCs not only can fine-tune the optical properties of the nanoclusters but also enable specific and simultaneous detection of Hg2+ and Co2+ ions via metallophilic Au+ -Hg2+ interaction and the Co2+ -thiol complexation effect, respectively. The feasibility of the device for detecting heavy metal ions at low concentrations in various environmental water samples is demonstrated. The Hg2+ and Co2+ ions can be seen simultaneously within 20 min with detection limits as low as 1.76 nm and 0.27 µm, respectively, lower than those of the regulatory restrictions on water by the US Environmental Protection Agency and the European Union. we expect this sensitive, selective, portable, and easy-to-use device to be valid for on-site multiple heavy metal ion pollution screenings in resource-constrained settings.

Manufacture and extraction of PLLA films with incorporated metal ions

Abstract For the in vitro examination of the effects on cells and tissues of metal ions derived from implants by wear and corrosion, a system is needed to release metal ions in a controlled and sustained manner. As small concentrations may have an impact on biological systems, a corresponding slow release over a defined period of time is necessary. Here, a manufacturing method of polymeric Poly(L-lactic acid) (PLLA) films with incorporated cobalt ions via dip coating is reported. The establishment of two analytical methods for the detection and quantification of cobalt ions is shown. High performance liquid chromatography enables cobalt quantification over a concentration range of 0.33 μg/mL up to 33 μg/mL in sample solutions. Extraction and detection of cobalt ions from solvent cast PLLA-cobalt-films shows the feasibility of the manufacturing method. Initial biocompatibility tests with manufactured PLLA-cobaltfilms showed no effects on adipose derived primary mesenchymal stem cells (adMSCs).

Quinoline-ampyrone functionalized azo dyes as colorimetric and fluorescent enhancement probes for selective aluminium and cobalt ion detection in semi-aqueous media

Two azo dyes (E)-4-((6-hydroxyquinolin-5-yl)diazenyl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (6QD) and (E)-4-((8-hydroxyquinolin-5-yl)diazenyl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (8QD) have been designed and synthesized. The structure of both dyes was confirmed by FTIR, NMR spectroscopy and mass spectrometry. The absorption and emission spectral analysis of 6QD and 8QD confirmed their selective turn-on behaviour towards Al3+ and Co2+ ions, respectively in MeOH:H2O (v/v = 1:1, HEPES buffer, pH = 7.2) at room temperature. The emission intensity of 6QD enhanced remarkably by 148-fold upon binding with Al3+ ion due to chelation-enhanced fluorescence (CHEF) effect and inhibition of photoinduced electron transfer (PET) phenomenon in the molecule. Emission behaviour of 8QD operates on CHEF and intramolecular charge transfer (ICT) mechanisms in presence of Co2+ ion which induced 26-fold enhancement in emission intensity of 8QD. Colorimetric studies showed prominent visual response for Al3+ and Co2+ ions allowing the real time analysis of these ions in their corresponding solutions. Other coexisting metal ions do not interfere with the detection of these metal ions. Job’s plot analyses revealed 1:1 binding stoichiometry for complexes 6QD-Al3+ and 8QD-Co2+. Association constants of complexes 6QD-Al3+ and 8QD-Co2+ were found to be 1.2 × 106 and 4 × 106 M−1, respectively which suggest good association of both probes with respective metal ions. The limit of detection of 6QD and 8QD was determined to be 1 × 10−8 M and 9.1 × 10−8 M respectively, which demonstrates the high sensitivity towards corresponding metal ions. Reversible studies confirmed that both probes 6QD and 8QD could be used as secondary sensor for EDTA2− anion. Furthermore, pH based absorption studies revealed that 6QD and 8QD can act as naked eye colorimetric probe for detection of hydroxyl ions at pH > 9.

Fluorescence Resonance Energy Transfer Detection of Cobalt Ions by Silver Triangular Nanoplates and Rhodamine 6G

In the present paper, the authors studied fluorescence resonance energy transfer (FRET) phenomenon between silver triangular nanoplates and bovine serum albumin (BSA)/Rhodamine 6G fluorescence complex, and established a fluorescence method for the detection of cobalt ions. We found that when increasing the silver triangular nanoplates added to certain concentrations of fluorescent bovine serum albumin (BSA)/Rhodamine 6G complex, the fluorescence of Rhodamine 6G would be quenched up to 80% due to the FRET between the quencher and donor. However, in the presence of cobalt ions, the disassociation of the fluorescent complex from silver triangular nanoplates occurred and the fluorescence of the Rhodamine 6G recovered. The recovery of fluorescence intensity rate (I/I0) has a good relationship with the cobalt ion concentration (cCO2+) added. Thus, the authors developed a fluorescence method for the detection of cobalt ions based on the FRET of silver triangular nanoplates and Rhodamine 6G.

Ultrasensitive chemiluminescence detection of sub-f M level Co(II) in capillary electrophoresis

A method of on-line ultrasensitive chemiluminescence detection with capillary electrophoresis for Co(II) is reported. Using our newly developed capillary electrophoresis with chemiluminescence detection system and novel mixing mode of the reagents, the effects of field-amplified injection on detection limits of metal ions were studied in detail. The sub-f M level (1.3·10 −16 M, 1.6×10 −24 mol, 1 molecule) detection of cobalt ions in ultradilute solution was performed. The catalytic behavior of the chemiluminescence reaction of luminol and hydrogen peroxide by cobalt ions and the reaction conditions, such as the concentration of luminol, H 2O 2, and pH of chemiluminescence reagent were investigated. The separation of f M level Co(II) and trace amounts of Ni(II) was performed successfully.

Intelligent sensor for metal ions based on fluorescence resonance energy transfer

We report a new type of remote optical sensor of metal ions in solution based on fluorescence lifetime quenching due to dipole-dipole energy transfer across a polymer-water interface. Ion selectivity is provided by spectral overlap between the sensor fluorescence and metal ion absorption. The sensor is demonstrated in the detection of cobalt ions in water at levels down to 17 mu g.