Detection Of Ni2 Research Articles

Ultrasensitive electrochemical sensor based on dimethylglyoxime/carbon paste electrode modified with a bimetallic nanocomposite for nickel detection in environmental water samples

To date, research in the monitoring of heavy metal pollution focuses on developing an advanced and selective sensor. In this study, an electrochemical sensor-based bimetallic nanocomposite modified dimethylglyoxime carbon paste electrode (DMG/CPE) was created to detect Ni2+ selectively. The bimetallic nanocomposite was prepared by depositing a thin layer of silver nanoparticles (AgNPs) on the surface of the magnetite (Fe3O4)/DMG/CPE electrode. The incorporation of Fe3O4 and AgNPs results in a synergistic effect, increasing electron transfer and expanding the electroactive surface area (from 2.78 mm2 to 3.81 mm2), hence leading to an increase in the peak current response (ΔIp = 26.15 ± 0.33 µA at modified CPE). The prepared AgNPs/Fe3O4/DMG/CPE electrode demonstrated excellent properties, allowing for a broad linear dynamic range lying between 2–10 nM; 10–100 nM; and 100–1000 nM and a limit of detection value of 0.6 nM (S/N = 3). Additionally, the developed sensor showed great sensitivity, selectivity, and reliability in the detection of Ni2+ in river water samples, making it promising for a sensitive and selective detection of Ni-contaminated water.

N’-(4-(diethylamino)-2-hydroxybenzylidene) isonicotinohydrazide based chemosensor for nanomolar detection of Ni(II) ion

ABSTRACT A novel Schiff base, N’-(4-(diethylamino)-2-hydroxybenzylidene) isonicotinohydrazide (S1) was synthesised by the condensation reaction between isonicotinohydrazide and 4-(diethylamino)-2-hydroxybenzaldehyde. The chemo-sensing behaviour of S1 towards Ni2+ was investigated and confirmed that the S1 exhibited fair selectivity and sensitivity. Furthermore, it was noted that there was no significant effect of co-existing cations and anions on the detection of Ni2+. The complexation ratio of S1 and Ni2+ was confirmed as 1:1 with Jobs continuous variation method and two isosbestic points on absorption titration further supported by DFT calculations. The binding constant (Kb) for S1+Ni2+ was calculated as 22,769 M−1 and 22,134 M−1. Moreover, the obtained limit of detection (LOD) for Ni2+ was found to be 375 nM. Finally, chemosensing applications of S1 as a paper test strip kit in the environmental monitoring assessment laboratory for the recovery of Ni2+ from real water samples were successfully designed and evaluated.

Selection of a metal ligand modified DNAzyme for detecting Ni2+

Nickel is a highly important metal, and the detection of Ni2+ using biosensors is a long-stand analytical challenge. DNA has been widely used for metal detection, although no DNA-based sensors were reported for Ni2+. DNAzymes are DNA-based catalysts, and they recruit metal ions for catalysis. In this work, in vitro selection of RNA-cleaving DNAzymes was carried out using a library containing a region of 50 random nucleotides in the presence of Ni2+. To increase Ni2+ binding, a glycyl–histidine-functionalized tertiary amine moiety was inserted at the cleavage junction. A representative DNAzyme named Ni03 showed a high cleavage yield with Ni2+ and it was further studied. After truncation, the optimal sequence of Ni03l could bind one Ni2+ or two Co2+ for catalysis, while other metal ions were inactive. Its cleavage rates for 100 μM Ni2+ reached 0.63 h−1 at pH 8.0. A catalytic beacon biosensor was designed by labeling a fluorophore and a quencher on the Ni03l DNAzyme. Fluorescence enhancement was observed in the presence of Ni2+ with a detection limit of 12.9 μM. The sensor was also tested in spiked Lake Ontario water achieving a similar sensitivity. This is another example of using single-site modified DNAzyme for sensing transition metal ions.

Simple and rapid colorimetric sensing of Ni(II) ions in tap water based on aggregation of citrate-stabilized silver nanoparticles

The presence of nickel in our water sources presents a danger to human health and aquatic organisms alike. Therefore, there is a need to detect and monitor nickel concentration in these sources. Current detection methods use instruments that are costly, resource intensive and require skilled personnel. Alternative methods that are simple and fast are needed. This study reports for the first time the development of a simple colorimetric assay for the detection of Ni2+ in aqueous solution using citrate-stabilized silver nanoparticles. Chemical synthesis method was employed using sodium borohydride and trisodium citrate as reducing and stabilizing agents, respectively. The characterization techniques used for obtaining spectral and morphological properties were ultraviolet-visible spectroscopy and transmission electron microscopy. The resultant silver nanoparticle solution was yellow in color and exhibited an absorbance peak at 392 nm. The full width at half maximum value was 57.8 ± 1.3 nm indicating particle monodispersity. For the morphology, the nanoparticles were spherical in shape with an average size of 10.4 ± 4.5 nm. Furthermore, the colorimetric properties of the silver nanoparticles for Ni2+ detection was investigated. Ni2+ was visually detected through a fast solution color change from yellow to orange. Monitoring of the absorbance showed a decrease in the original 392 nm peak and broadening of the surface plasmon absorption band. These changes are attributed to the aggregation of the nanoparticles due to Ni2+ addition which was confirmed by the transmission electron microscopy imaging. The absorption ratio (A510/A392) was plotted against varying Ni2+ concentration and it exhibited a good linear correlation from 0.7 to 1.6 mM with an R2 of 0.9958. The limits of detection and quantification were 0.75 and 1.52 mM, respectively. Additionally, the assay was tested against other common ions and showed excellent selectivity for Ni2+. Finally, the assay was successfully tested to detect Ni2+ in tap water samples with an average difference of 16% from prepared concentrations. Overall, the study showed the potential of using citrate-stabilized silver nanoparticles as a colorimetric reagent for detecting Ni2+ in aqueous solution.

Antibacterial activity and possible mechanisms of one-step synthetic laminated flower-like nickelous(II) hydroxide

It is very urgent to design and fabricate a new generation of bactericidal materials for confronting the increasing prevalence of antibacterial resistance. Here, we propose laminated flower-like nickelous(II) hydroxide as antibacterial agent and explore its possible antibacterial action. The nickelous(II) hydroxide were synthesized by simple one-step hydrothermal process. The antibacterial properties of nickelous(II) hydroxide were tested by bacterial growth curves and colonies growth on agar nutritive plates. The nickelous(II) hydroxide exhibited a strong, stable and long-term antibacterial activity and killed > 95.0% of both the Gram-negative bacteria Escherichia coli and the Gram-positive bacteria Staphylococcus aureus at 250 μg/mL. Antibacterial action was investigated by scanning electron microscopy, transmission electron microscopy, detection of Ni2+ residual, measurement of DNA and RNA release and reactive oxygen species generation analysis. Mechanistically, it killed both Gram-positive and Gram-negative bacteria through physical disruption of the cell membrane structure, causing a loss of cell viability. The antibacterial action would endow nickelous(II) hydroxide with the ability to escape some known mechanisms of antibacterial resistance as a promising long-term bactericide.

Complexation-Based Detection of Nickel(II) at a Graphene-Chelate Probe in the Presence of Cobalt and Zinc by Adsorptive Stripping Voltammetry.

The adsorptive stripping voltammetric detection of nickel and cobalt in water samples at metal film electrodes has been extensively studied. In this work, a novel, environmentally friendly, metal-free electrochemical probe was constructed for the ultra-trace determination of Ni2+ in water samples by Adsorptive Cathodic Stripping Voltammetry (AdCSV). The electrochemical platform is based on the adsorptive accumulation of Ni2+ ions directly onto a glassy carbon electrode (GCE) modified with dimethylglyoxime (DMG) as chelating agent and a Nafion-graphene (NGr) nanocomposite to enhance electrode sensitivity. The nafion-graphene dimethylglyoxime modified glassy carbon electrode (NGr-DMG-GCE) shows superior detection capabilities as a result of the improved surface-area-to-volume ratio and enhanced electron transfer kinetics following the incorporation of single layer graphene, while limiting the toxic effects of the sensor by removal of the more common mercury, bismuth and lead films. Furthermore, for the first time the NGr-DMG-GCE, in the presence of common interfering metal ions of Co2+ and Zn2+ demonstrates good selectivity and preferential binding towards the detection of Ni2+ in water samples. Structural and morphological characterisation of the synthesised single layer graphene sheets was conducted by Raman spectrometry, HRTEM and HRSEM analysis. The instrumental parameters associated with the electrochemical response, including accumulation potential and accumulation time were investigated and optimised in addition to the influence of DMG and graphene concentrations. The NGr-DMG-GCE demonstrated well resolved, reproducible peaks, with RSD (%) below 5% and a detection limit of 1.5 µg L−1 for Ni2+ reduction at an accumulation time of 120 s. The prepared electrochemical sensor exhibited good detection and quantitation towards Ni2+ detection in tap water samples, well below 0.1 mg L−1 set by the WHO and EPA standards. This is comparable to the South African drinking water guidelines of 0.15 mg L−1.

A colorimetric probe for the detection of Ni2+ in water based on Ag-Cu alloy nanoparticles hosted in electrospun nanofibres

A Ni 2+ based colorimetric probe based on glutathione-stabilized silver/copper nanoparticles (GSH-Ag-Cu alloy NPs) in an electrospun polymer matrix is reported. Glutathione-Ag-Cu alloy NPs were characterized by ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The freshly synthesized GSH-Ag-Cu alloy NPs in a polymer matrix were black in colour due to an intense surface plasmon absorption band at 424 nm. However the electrospun nanocomposite fibres were green in colour and in the presence of Ni 2+ the green GSH-Ag-Cu alloy NP fibres were discoloured. The sensitivity of the GSH-Ag-Cu alloy NPs towards other representative transition, alkali and alkali earth metal ions was negligible. The effect of the concentration of Ni 2+ on the nanocomposite fibres was evaluated and the ‘eye-ball’ limit of detection was found to be 5.8 μg/mL. Keywords : colorimetric probes, alloy nanoparticles, electrospun nanofibres, heavy metal determination

Enhancement the detection of Ni2+ and Zn2+ ions using nanostructure of synthesized dithiol surfactants with gold nanoparticles

Here in, the nanostructure of dithiol surfactants were synthesized with gold nanoparticles (AuNPs). The nanostructure of these surfactants was investigated using FTIR, UV, XRD, and TEM techniques. The surfactants under investigation show good ability for assembling on AuNPs. The alkyl chain length shows strong effect on the stabilization of the nanostructure of these surfactants. The detection of Ni2+ and Zn2+ ions in water solution was investigated using UV spectrophotometer. The data show that the sensitivity of the nanostructure of surfactants towards the detection of Ni2+ and Zn2+ ions is more than that of the individual surfactants.

Controlled Formation of Ni(DMG)2 Microrods/Tubes by Manipulating the Kinetics of Chemical Reactions and Their Application in Naked-Eye Sensors

We have demonstrated controlled preparation of Ni(DMG)2 microrods/tubes via chemical reaction method. By manipulating the reaction kinetics via the concentration of reactants, shapes of the resulting microstructures can be easily tuned from microrods to microtubes. Size of the resulting products can also be controlled through changing the reaction temperatures. It was proposed that under high reactants' concentrations, molecules will prefer to grow at corners or edges of nuclei with high free energies, to reduce the total energy in the system, which would lead to partial or complete hollow interiors and eventually resulted in mircotubes. The fact that DMG show high selectivity with Ni2+ and accompanied with obvious color change enable us to fabricate test strip for naked-eye detection of Ni2+. Benefit from the large surface areas of DMG nanoparticles on the test strip, the detection limit is improved by two orders over that of conventional solution method. This strategy is sensitive, simple and easy to handle, thus expected to possess potentials for the practical Ni2+ detection applications.

Detection of Ni2+ by a dimethylglyoxime probe using attenuated total-reflection infrared spectroscopy.

A new analytical approach for the detection of Ni2+ utilizing an attenuated total reflection (ATR) technique is discussed in this paper. Nickel detection was accomplished on a silicon ATR parallelogram crystal uniformly coated by a ca. 1.5-microm Nafion film embedded with dimethylglyoxime (DMG) probe molecules. The detection of Ni2+ is based on the appearance of a unique infrared absorption peak at 1572 cm(-1) that corresponds to the C=N stretching mode in the nickel dimethylglyoximate, Ni(DMG)2, complex. The suitable operational pH range for the nickel infrared sensor is between 6 - 8. High alkalinity in the sample solution causes a leaching of Ni(DMG)2. The detection limit of the nickel infrared sensor is 1 ppm in a sample solution of pH = 8. Interference studies revealed that Cu2+ could compete with Ni2+ for the DMG sites in the Nafion matrix. The new nickel detection methodology can be potentially utilized, after further improvement, in field analysis to locate hot spots contaminated with a high ppm of Ni2+.