Ratio Of Metal Content Research Articles

Electrochemical sensor based on hollow Au/Pd/Ag dendrites prepared by galvanic replacement from a choline chloride-ethylene glycol deep eutectic solvent

This study presents a simple approach to fabricating a hollow dendritic Au/Pd/Ag electrode through a galvanic replacement reaction (GRR) in a choline chloride-ethylene glycol deep eutectic solvent. The resulting electrode's morphological, structural, and compositional features were characterized using SEM, TEM, XRD, and XPS techniques, with the XPS depth profile providing insights into metal content ratio variations along the electrode's depth. The results emphasize the significant impact of immersion time on both morphological evolution and composition. Cyclic voltammetry investigations revealed significantly enhanced current density in furaltadone (FTD) detection compared to bimetallic and single metallic electrodes. The proposed electrochemical sensor exhibited a dynamic linear range for FTD spanning 1.67–625 μM, accompanied by a low detection limit of 91.7 nM, as confirmed by differential pulse voltammetry (DPV) quantitative experiments. The selectivity, reproducibility, stability, and recovery of the as-prepared sensors were evaluated, particularly in aquaculture water samples, underscoring the practical applicability of the electrodes for furaltadone sensing. This innovative trimetallic electrode design opens avenues for advanced electrochemical sensors with enhanced performance characteristics.

Influence of the method of gas supply to the chamber on the processes of reactive magnetron sputtering of Ti-Al composite target

The paper demonstrates study results of the processes of reactive magnetron sputtering of a Ti-Al composite target in an Ar/O2 gas mixture with various methods of gas supply to the chamber. It has been established that, regardless of the method of gas supply, when changing the oxygen concentration in the Ar/O2 gas mixture, the ratio of the Al and Ti content in the deposited Ti1-xAlxOy films changes. The metal content ratio in the deposited films varies in proportion to the change in the ratio of the control lines intensities of the optical emission of aluminum AlI (396.15 nm) and titanium TiI (395.82 nm) in plasma. This makes it possible to effectively use the method of optical emission spectroscopy to predict and control the content of metals in deposited films. Based on studies of the dielectric characteristics of deposited Ti1-xAlxOy films, it was discovered that with separate gas supply (Ar is supplied to the target region, O2 is supplied to the substrate region), in contrast to the joint gas supply (the Ar/O2 gas mixture is supplied to the target region), it is possible to deposit dielectric films in the transient mode at relatively high sputtering rates. In this case, the oxygen supply to the substrate region makes it possible to increase the oxygen content in the films up to 60-64%. Keywords: preactive magnetron sputtering, composite target, thin films, titanium-aluminum oxide, elemental composition, permittivity, dielectric loss tangent.

Study on the Performance of Ag-Cu Bimetal SERS Substrate

SERS has become a powerful trace detection technology, but its practical application is often limited by the fixed optical properties of cast metals (Au, Ag and Cu). In this paper, the bimetallic nanostructures prepared by changing the metal content ratio can regulate the different optical responses of the substrate. In addition, it was found that the scale of moth wings (MW) with 3D grating-like uniform nanoarrays using bioscaffold can provide a consistently high-density ‘hot spot’ for the as-prepared plasmonic substrate. Here, two different methods (i) co-sputtered with different times and (ii) sputtered with sequentially alternating to form a stratified structure on the MW were employed for the fabrication of SERS-active substrates, and they were named AgCu@MW and Ag@Cu@MW, respectively. The comparison SERS measurement results of the above two substrates by using probe molecules R6G and MB show that the stratified structure of the Ag@Cu@MW-3 substrate has higher SERS performance. This strategy can not only prepare plasma substrates with on-demand optical responses but also provide new ideas for the preparation of conventional biomimetic nanomaterials.

Visible-light-driven reduction of nitrostyrene utilizing plasmonic silver nanoparticle catalysts immobilized on oxide supports

Abstract The localized surface plasmon resonance (LSPR) mediated enhanced chemical activity can be entitled as a promising strategy for efficient solar to chemical energy conversion. To tune the selectivity of a desired product in a chemical reaction is of paramount importance yet a great challenge. In this paper, a new strategy to effectively enhance the selectivity of the product formation under visible light irradiation is reported. A series of Ag catalysts deposited on metal oxide support materials (TiO2, ZrO2, Al2O3 and CeO2) along with their preparative techniques, optimum metal content ratio and effect of different wavelength of light is explored for the chemoselective reduction of p-nitrostyrene to p-aminostyrene under visible light irradiation. The prepared catalysts were characterized by a range of physicochemical techniques including UV–vis, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The reduction reaction was carried out in ethanolic suspension at room temperature and pressure utilizing ammonia borane (AB) as an in-situ source of H2. The reaction results displayed 100% conversion with a maximum chemoselectivity of 81% shown by Ag/TiO2 under light irradiation conditions. The high chemoselectivity could be attributed to the preferential alignment of polar nitro group on the surface of plasmonic silver under light irradiation conditions.

Gelatin biotemplated platinum aerogels

ABSTRACTHere gelatin biotemplated platinum aerogels were prepared from gelatin hydrogels equilibrated in K2PtCl4solutions ranging from 1-250 mM and reduced with sodium borohydride before supercritical drying in liquid CO2. Scanning electron microscopy revealed an average ligament diameter of 40.6 ± 9.7 nm and a pore size range of ∼10 – 200 nm. Thermogravimetric analysis correlated the ratio of metal content to biotemplate mass as a function of equilibrated platinum ion solution, and X-ray diffractometry indicated platinum metal with no detectable oxide phases. Electrochemical impedance spectroscopy indicated a specific capacitance of 1.92 F/g, with a corresponding specific electrochemical accessible surface area of 6.39 m2/g. Cyclic voltammetry performed in H2SO4demonstrated biotemplated platinum aerogel potential for catalytic and energy storage applications.

Human exposure to heavy metals and possible public health risks via consumption of wild edible mushrooms from Slovak Paradise National Park, Slovakia

The contamination level of 92 samples (12 species) of wild edible mushrooms and underlying substrates with heavy metals (Cd, Cu, Hg, Pb and Zn) in the Slovak Paradise National Park that borders with a region of historical mining and processing of polymetallic ores, were determined. The collected samples were analyzed using of atomic absorption spectrophotometry. The metals were determined separately in hymenophore (H) and rest of fruit bodies (RFB). Bioaccumulation factor as well as ratio of metal content in H and RFB were calculated. Cadmium and lead contents in hymenophore exceeded statutory limits of the EU (Cd: 0.5 mg/kg dry weight (dw), Pb: 1.0 mg/kg dw) for edible mushrooms in 96% and 83% of the samples, respectively. The risk from the consumption of the collected mushroom species was calculated based on the provisionally tolerable weekly intake (PTWI) values, and the highest health risk arising with consumption of particularly Macrolepiota procera, Marasmius oreades and Russula vesca from the observed area was demonstrated. It was shown that average weekly consumption of tested mushrooms species results the threat of exceeding of PTWI limits in the case of cadmium values (by 164%, 86% and 4% of PTWI for M. oreades, R. vesca and R. puellaris, respectively) and of mercury (by 96% of PTWI for M. procera) but not lead.

A Study on Toxic Acidic Vapor Removal Behaviors of Continuously Nanostructured Copper/Nickel‐Coated Nanoporous Carbons

Nanostructured copper (Cu)/nickel‐ (Ni‐) coated nanoporous carbon sheets (NCS) were prepared to improve the toxic acidic vapor (hydrogen chloride, HCl) removal efficiency of NCS using a continuous bimetal electroplating method at various metal content ratios. The surface morphology and nanostructure of Cu/Ni‐NCS were observed by scanning electron microscopy and X‐ray diffraction, respectively. N2/77 K adsorption isotherms were investigated using the Brunauer‐Emmett‐Teller equation. HCl vapor removal efficiency was confirmed using two types of detection techniques: a gas detecting tube for low concentrations and gas chromatography for high concentrations. HCl removal efficiency was improved mainly in the copresence of nanostructured Cu/Ni clusters compared to the efficiencies of the as‐received and single‐metal‐plated NCS. In particular, the removal efficiency of Cu/Ni‐3 was increased by 270% compared to that of as‐received sample, but Cu/Ni‐5 showed lower efficiency than Cu/Ni‐3, indicating that suitable metal composition on NCS can accelerate HCl removal behaviors of the NCS.

Effect of the cp4-epsps Gene on Metal Bioavailability in Maize and Soybean Using Bionic Gastrointestinal Tracts and ICP-MS Determination

The transformation and metabolism of dietary compounds are affected significantly by gut microbiota. Hence, gut microbiota are used to improve bionic gastrointestinal tracts. The effect of the cp4-epsps gene on metal bioavailability was proved by the comparison of the affinity-liposome metal content ratio (AMCR) in transgenic and conventional crops. The bioavailability of V, Mn, Co, Ga, Ag, Ba, and Pb in roundup ready soybean decreased significantly because the ratio of AMCR (R(AMCR)) in the transgenic crop and its corresponding conventional type ranged from 0.36 to 0.69. In roundup ready maize, metal bioavailability decreased for Li and Cr (i.e., R(AMCR) was 0.26 and 0.39, respectively) but increased for V, Co, and Pb (i.e., R(AMCR) was 1.48, 2.07, and 2.12, respectively). Compared with conventional crops, safe dosage and maximum consumption of roundup ready crops were 1.59 times for soybean and 0.78 times for maize.

Heavy Metal Uptake By Scirpus Littoralis Schrad. From Fly Ash Dosed and Metal Spiked Soils

Scirpus littoralis is a wetland plant commonly found in Yamuna flood plains of Delhi, India. The ability of Scirpus littoralis to take up and translocate five metals- Mn, Ni, Cu, Zn and Pb from fly ash dosed and metal spiked soils were studied under waterlogged and field conditions for 90 days. Scirpus littoralis accumulated Mn, Ni, Cu, Zn and Pb upto a maximum of 494.92, 56.37, 144.98, 207.95 and 93.08 ppm dry wt., respectively in below ground organs (BO) in 90 days time. The metal content ratios BO/soil (B/S) were higher than shoot/soil ratios (T/S) for all the metals, the highest being for Ni. Metal ratios BO/water (B/W) were also higher than shoot/water (T/W) ratios but the B/W ratio was maximum for Zn. The changes in nutrient status (N, P) in soil water and plants were also studied at interval of 30 days. The Pearson's correlation between metal uptake and N, P uptake were calculated. All the metals except Ni showed negative correlation with nitrogen but they were all non-significant. However, P uptake showed positive correlations with all the metals and all were significant at 1% confidence limit.

Characteristics of (Cr1-x, Alx)N Films Prepared by Pulsed Laser Deposition

Chromium aluminum nitride ((Cr1-x, Alx)N) films have been successfully prepared by pulsed laser deposition (PLD). Experiments were carried out by changing the surface area ratio of the target (Al/(Cr+Al)) from 0 to 100%. From the results of energy-dispersive X-ray spectroscopy (EDS) and Rutherford backscattering spectroscopy (RBS), we have found that the metal content ratio of the film agreed well with the surface area ratio of the target. The hardness of the (Cr1-x, Alx)N films showed the maximum value (HV∼3000) at x=0.75. Phase transition from the B1 (NaCl) structure to the B4 (würtzite) structure occurred above x=0.75, which was in reasonable agreement with the theoretical prediction. The result of the oxidation test revealed that the CrN film was oxidized at approximately 600°C, whereas in the (Cr0.5, Al0.5)N film, the existence of oxide was not detected in the annealing temperature range of RT to 900°C.

The concentrations of the bound metals in hepatic metallothionein of rats injected with cadmium.

The relationship between the amount of injected Cd and the bound metal concentrations of rat hepatic metallothionein (MT) was investigated. Rats were injected subcutaneously with 0.1, 0.3, 0.6 or 1.2 mg Cd (single injection) or 0.1 mg Cd 3, 6 or 12 times on successive days (plural injection). When the MT induced by single injection was compared with that induced by plural injection, there was no difference in the total concentration of three bound metals (Cd, Cu and Zn) though there were small differences in the concentration of each metal in the MT injection of the same amount of Cd. The total bound metal concentration increased and each metal content ratio changed depending on the total amount of injected Cd. Due to turnover, the content ratios of Cd and Zn in the MT became lower and higher than those in the initial induced MT, respectively, and the total bound metal concentration decreased.

Metal content ratio as a sensitive indicator of pulmonary edema

The sensitivity to detect edema fluid in the lungs of rats exposed to 4, 2, 0.8, and 0.4 ppm O 3 was estimated using the metal content ratio (Ca/Mg) and wet/dry weight ratio methods. Metal content ratios were determined by inductively coupled plasma-atomic emission spectrometer (ICP-AES). The detection limits were 0.8 and 2.0 ppm for the former and latter methods, respectively. A transitory increase of edema fluid was observed at day 1 in 0.8 and 0.4 ppm experiments by the Ca/Mg ratio method.

The determination of trace metals in cladophora glomerata— c. glomerata as a potential biological monitor

A differential pulse anodic stripping voltammetry method has been developed for the determination of Zn, Cd, Pb and Cu in Cladophora glomerata. The method has been applied to samples taken in August from a remote island in Lake Ontario (Main Duck) and a shore site near Kingston, Ontario (Deadman Bay). Trace metal contents and concentration factors (CF) for the two samples are: Zn Cd Pb Cu Deadman Bay 23.7 3.9 9.5 7.2 μ/g CF/10 3 2.9 49 16 2.2 Main Duck 8.2 1.4 12.2 6.4 μg/g CF/10 3 1.0 18 20 1.9 The concentration factors are the ratio of metal content in the Cladophora (μg/g) to the best value for the metal content of filtered Lake Ontario water (μg/ml); the factors range from 1.0 × 10 3 to 49 × 10 3 for the samples and elements studied. It is postulated that C. glomerata can act as a biological monitor, concentrating the trace metals present in the aqueous environment with a reasonably constant CF for each element.