Nickel contamination analysis at cost-effective silver printed paper-based electrodes based on carbon black dimethylglyoxime ink as electrode modifier

Electrochemical detection of metal cations at paper-based sensors has been suggested as an attractive alternative to current spectroscopic and chromatographic detection techniques due to the ease of fabrication, disposable nature, and low cost. Herein, a novel carbon black (CB), dimethylglyoxime (DMG) ink is designed as an electrode modifier in conjunction with 3-electrode inkjet-printed paper substrates for use in the adsorptive stripping voltammetric electroanalysis of nickel cations in water samples. The developed method provides a novel, low-cost, rapid, and portable adsorptive stripping detection approach towards metal analysis in the absence of the commonly used toxic metallic films. The study demonstrated a novel approach to nickel detection at paper-based sensors and builds on previous work in the field of paper-based metal analysis by limiting the use of toxic metal films. The device sensitivity is improved by increasing the active surface area, electron transfer kinetics, and catalytic effects associated with non-conductive dimethylglyoxime films through CB nanoparticles for the first time and confirmed by electroanalysis. The first use of the CB-DMG ink allows for the selective preconcentration of analyte at the electrode surface without the use of toxic Mercury or Bismuth metallic films. Compared to similarly reported paper-based sensors, improved limits of detection (48 µg L-1), selectivity, and intermetallic interferences were achieved. The method was applied to the detection of nickel in water samples well below World Health Organization (WHO) standards.

Structural Studies of Some Sulphur Bonding Ligands

<p>This thesis is a study of the structures and energetics of the metal complexes of dithizone, C6H5.N:N.C(S).NH.NH.C6H5, and thiocarbohydrazide, H2N.HN.C(S).NH.NH2. Dithizone was first prepared and studied by E. Fisher as part of his classic work on phenylhydrazine. It is a weak acid capable of forming intensely coloured metal complexes with at least twenty three elements and, since the work of Walter and H. Fischer, has been used extensively for trace metal analysis, particularly in solvent extraction procedures. The applications of dithizone in analytical chemistry have been covered in numerous review articles and have also been the subject of a book.</p>

Structural Studies of Some Sulphur Bonding Ligands

<p>This thesis is a study of the structures and energetics of the metal complexes of dithizone, C6H5.N:N.C(S).NH.NH.C6H5, and thiocarbohydrazide, H2N.HN.C(S).NH.NH2. Dithizone was first prepared and studied by E. Fisher as part of his classic work on phenylhydrazine. It is a weak acid capable of forming intensely coloured metal complexes with at least twenty three elements and, since the work of Walter and H. Fischer, has been used extensively for trace metal analysis, particularly in solvent extraction procedures. The applications of dithizone in analytical chemistry have been covered in numerous review articles and have also been the subject of a book.</p>

Synthesis of some Novel Mixed Ligand Complexes of Ni(II) and their Characterization

A new series of metal Complexes were prepared by refluxing nickel chloride with hot methanolic solution mixture of 8-Hydroxyquinoline and Schiff bases(L1-L6). Schiff base ligands were synthesised by the condensation of 4-aminopheno, 4-aminosalicylic acid, 2-aminobenzthiazole with salicylaldehyde and vanillin. The metal complexes have been characterised by gravimetric metal analysis, magnetic moment,conductivity measurement, 1HNMR and IR analysis.

HEAVY METAL POLLUTANT SORPTION IN AQUATIC ENVIRONMENT BY MICROALGAE CONSORTIUM

<span id="docs-internal-guid-d0229f1b-7fff-d768-d24f-5faaaf7907f0"><span>Industrial waste that contains heavy metal can cause environmental problem because of its toxicity, persistency and accumulation level in the environment. Biosorption process is highly influenced by temperature, pH, light, contact time, and ratio of surface area. Microalgae which possess two functional groups that are able to react on metal ion in a solution can be exploited to overcome environmental pollution due to heavy metal compound. Closed cultivation system in a photobioreactor is utilized to overcome contamination and evaporation problems on open pond system. Heavy metal analysis is conducted by utilizing Atomic Absorption Spectroscopy (AAS), Fourier Transform Infra-Red (FTIR), and Scanning Electron Microscope (SEM). This article provides information on biosorption as alternative technology to overcome heavy metal in water areas with no side effects on the environment with advantages of the absence of secondary pollutants, high level of efficiency, and relatively economic compared to physic-chemical method heavy metal removal methods</span></span>

Spatial Variation Study of Heavy Metal in Ground Water of Southern Part of Upper Berach River

The present study was conducted to study heavy metal pollution in ground water of southern part of Upper Berach river. The water samples for the heavy metal analysis were collected from the open well of the 38 locations from Upper Berach river to find out concentration of different heavy metal such as Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn), Cadmium (Cd), Lead (Pb) and Nickel (Ni). The different heavy metals thematic maps of study area were prepared under GIS environment and the spatio-temporal variations of these parameters were analyzed. Results of the study indicates that about 57.94 per cent area shows Fe within BIS acceptable limit (< 0.3 mg/lit) and 42.06 per cent area show exceed Fe above acceptable limit of drinking purpose. About 42.03 per cent area shows Mn within BIS acceptable limit (< 0.1 mg/lit) and 57.97 per cent area shows Mn above permissible limit of drinking purpose.

Toxic metal analysis of external and internal compositions and lixiviation pattern of costume jewelry

Costume jewelry may expose skin to toxic metals due to sweat and friction, causing intoxications. An investigation was conducted over costume jewelry rings to study its behavior and verify its safety throughout their use, regarding toxic metal contamination. Qualitative and quantitative elemental analysis of the internal and external layers of the ring samples (costume jewelry) were made through X-Ray Fluorescence Spectrometry (XRF) and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The ring samples were also immerged in a synthetic sweat solution for 30 days. The lixiviated solution and post treated surfaces were analyzed by ICP-OES and Search Electron Microscopy (SEM), respectively. Metals such as Cu, Cd, Cr and Ni were identified in the surface composition, as well in the composition of the digested samples. The synthetic sweat eroded the rings surfaces, and metals such as Cd and Mn were lixiviated by it. The results indicate the presence and lixiviation of harmful metals that may cause health and environmental problems.

Evaluation of Heavy Metal Contents and Potential Human Health Risk Assessment of Selected Canned Sardines Fish Sold in Yenagoa, Nigeria

Canned sardine fish is consumed regularly in all countries. The levels of heavy metals which are present in the environment could constitute a hazard to food security and public health. These can be accumulated in aquatic animals such as fish. In this study, selected heavy metals: Copper (Cu), Nickel (Ni), Chromium (Cr), Zinc (Zn), Cadmium (Cd), Manganese (Mn), Lead (Pb) and Iron (Fe) were evaluated in Sardines that are commonly consumed in Nigeria. Eight different brands of canned sardines were purchased in Yenagoa and were taken to the Laboratory for heavy metal analysis. Standard wet digestion procedure was adopted for sample preparation while Atomic Absorption Spectrophotometer (AAS) technique was adopted for metal analysis. The results show that heavy metal concentrations of Fe in the samples were above World Health Organization (WHO) and United States Environmental Protection Agency (USEPA) permissible limits, while Zn was below the permissible limits. However, Pb, Cu, Cd, Cr, Ni and Mn were below detectable limits in all the samples. Daily intake of metal (DIM) values in the sardine samples for Zn and Fe were significantly lower than the recommended daily intake and the upper tolerable daily intake levels. The Health risk index (HRI), Target hazard quotient (THQ) and Hazard Index (HI) for Zn and Fe in this study were less than 1(˂1) for both adult and children, therefore, the canned sardines does not pose a potential human health risk concern for the consumers. However, the high Fe concentrations in all the sardine samples may cause public health concern as they are above WHO and USEPA tolerable limits.