As a stable isotope, boron plays an important role in hydrogeology, environmental geochemistry, ore deposit geochemistry and marine paleoclimatology. However, there is no report of boron isotopic ...composition in gypsum. This is mainly confined to complete dissolution of Gypsum by water or acid. In this study, gypsum was converted to calcium carbonate (CaCO3) with ammonium bicarbonate(NH4HCO3) by two steps at 50°C. In every step, the mass ratio of NH4HCO3/CaSO4·2H2O was twice, and conversion rate reached more than 98%. Converted CaCO3 was totally dissolved with hydrochloric acid (the dissolution rate was over 99%). In order to overcome the difficulties of the matrix interference and the detection limit of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), we use Amberlite IRA 743 resin to purify and enrichment the boron at first, then eluting boron from the resin with 10mL 0.1mol/L hydrochloric acid at 75°C. The boron isotopic composition of natural gypsum samples was determined using positive thermal ionization mass spectrometry (P-TIMS). The boron isotopic composition of gypsum may be an excellent indicator for the formation environment.
As a stable isotope, boron plays an important role in hydrogeology, environmental geochemistry, ore deposit geochemistry and marine paleoclimatology. However, there is no report of boron isotopic composition in gypsum. This is mainly confined to complete dissolution of Gypsum by water or acid. In this study, gypsum was converted to calcium carbonate with ammonium bicarbonate by two steps at 50°C (Fig. 1). In every step, the mass ratio of NH4HCO3/CaSO4·2H2O was twice, and conversion rate reached more than 98%. It was completely dissolved with hydrochloric acid (the dissolution rate was over 99%). In order to overcome the difficulties of the matrix interference and the detection limit of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), we use Amberlite IRA 743 resin to purify and enrichment the boron at first, then eluting boron from the resin with 10mL 0.1mol/L hydrochloric acid at 75°C. The boron isotopic composition of natural gypsum samples was determined using positive thermal ionization mass spectrometry (P-TIMS) based on Cs2BO2+. The boron isotopic composition of gypsum may be an excellent indicator for the formation environment. Display omitted
Recently there has been an influx of silver infused food packaging materials that claim to enhance the shelf-life of stored food. We tested commercially available normal plastic packing material (S1) ...and two packing materials (S2 and S3) which claimed to contain silver to enhance shelf-life of stored food for the presence of silver and its antibacterial performance. Microwave assisted acid digestion of the plastic material and ICP-OES analysis confirmed the presence of silver in S2 (103 μg/g) and S3 (74 μg/g) but not in S1. Migration studies showed that 12–14% of silver incorporated into the plastic could leach into milk (used as a food simulant). Shelf-life studies conducted using milk showed that in comparison to normal plastic materials (S1), those containing silver (S2 and S3) had no functional advantage but slightly enhanced the microbial growth. Further studies showed that sub-lethal concentration of silver generates reactive oxygen species (ROS) within bacterial cells (Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923) accompanied by increased cell proliferation and biofilm formation suggestive of a hormetic effect. In short, these studies showed that the incorporation of silver at low concentration in packaging materials may not provide a functional advantage, but mitigate the migration of silver into the stored food products at sub-lethal concentration and may induce bacterial hormesis and accelerate food spoilage.
•Evaluated food packaging materials with claims on antimicrobial silver technology.•ICP-OES based determination showed nominal levels of silver in packaging material.•Low levels of silver had no functional advantage in improving shelf-life of food.•Sub-lethal levels of silver showed hormesis by inducing mild oxidative stress.•Bacterial viability and biofilm formation increased at sub-lethal levels of silver.
•Initial corrosion of carbon steel was accelerated by decreasing pH.•FeCO3 layer formation and subsequently passivation were promoted by decreasing pH.•Dissolved oxygen is shown to substantially ...affect corrosion in amine solutions.•A dominant effect of dissolved oxygen is to retard protective layer formation.•pH stabilization is a possibly effective way to reduce corrosion for CO2 capture.
A pH stabilization method was investigated to mitigate corrosion in aqueous 5M monoethanolamine for post-combustion CO2 capture. The room temperature pH of a naturally aerated CO2-loaded solution (i.e., 9.7) was adjusted with NaHCO3 powders to 9.3 and 9.1, and its effect on corrosion of A106 carbon steel was studied. Lower pH initially accelerated corrosion but promoted protective FeCO3 layer formation and subsequently A106 passivation (i.e., Fe3O4 formation). Dissolved oxygen also played a pivotal role by functioning as an additional oxidizer, retarding FeCO3 formation via preferentially oxidizing Fe2+ to form rust, and promoting passivation of A106 under the FeCO3 layer.
Simple concepts that control the amount of analyte, solvent aerosol and solvent vapor that enter the plasma are used to explain changes in analyte transport efficiency as a function of sample uptake ...rate in pneumatic nebulizer/spray chamber sample introduction systems. These include droplet-droplet collision/coalescence, evaporation of solvent from the sample aerosol and droplet impact on the walls of the spray chamber. We show that even small (2 to 5 μm diameter) droplets have a poor (<12%) transport efficiency through the spray chamber when the sample uptake rate is 1 mL/min. A dual nebulizer system and video are used to assess the role of droplet-droplet collisions/coalescence and aerosol evaporation in controlling sample transport efficiency as a function of sample uptake rate. The impact of water vapor that evaporates from the wall of the spray chamber and from evaporation of solvent from the sample aerosol are described with experimental evidence. Sample transport efficiencies for “conventional” nebulizers and micronebulizers are found to be similar when compared at the same sample uptake rates from 0.02 to 1.0 mL/min. The stability of signals when using “conventional” and micronebulizers at sample uptake rates less than 0.05 mL/min are compared. The impact of water vapor loading and water aerosol loading are investigated using a heated sample introduction system that efficiently evaporates the solvent from aerosol droplets and a vibrating mesh nebulizer than can provide virtually 100% aerosol transport efficiency at aerosol transport rates up to 0.3 mL/min, respectively.
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•Key processes that control analyte transport efficiency through spray chamber.•Extent of droplet-droplet collision/coagulation, droplet evaporation.•Video of droplet impact on spray chamber walls even at 2–10 μL/min uptake rate.•Separately assess solvent vapor, aerosol load without extinguishing plasma.•Analyte transport efficiency: micronebulizers versus “conventional” nebulizers.
The Cotopaxi Volcano is one of the most active stratovolcanoes in the world. It is located in the center of Ecuador, surrounded by densely populated cities as Latacunga, Machachi, or Sangoquí, in ...which the agricultural sector is very important for economic development. Ash emissions and phreatomagmatic eruptions characterized the eruptive process of Cotopaxi volcano in august 2015. A mineralogical study of the ashes showed the presence of heavy metals, which could have been transferred to the soil and could affect agricultural and livestock activities. To evaluate the relationship between the concentrations of Cd, Cu, Pb, Hg, Cr, Co, Ni, Zn and as between the soil, ash and the comparison with local regulations, three farms (Altamira farm, San Ramon farm and La Laguna farm) in the Canton of Mejía were defined as the study area. In those locations, the soil samples were georeferenced with a handheld GPS. The analysis was carried out before acid digestion (EPA 3050B1 method) in an ICP-OES and AMA 254 atomic absorption spectrophotometer. The metals analyzed were kept within limits defined in TULSMA Book VI: Annex 2 Soil Resource local regulations. In order to improve the visibility of the study, the presentation of the results was carried out in an open-access geoportal implemented in proprietary software. This geoportal allows the dynamic and interactive visualization of the different concentrations of heavy metals in their corresponding location.
Food security is a priority issue for sustainable global development. Metal uptake by plants could have a significant impact on crop quality in areas of rapid industrialization with high fallout of ...airborne particles. In this study, concentrations of some heavy metals (copper, Cu; zinc, Zn; and lead, Pb) in flour samples supplied in Çorum, defined as one of the “New Industry Focus”, were investigated using inductively coupled plasma-optical emission spectrometry (ICP-OES) to determine the heavy metal contamination. The results showed that the concentration of Pb in all samples examined exceeded the maximum permissible limit. To monitor the increase in Pb concentration and its relationship with air pollution, a two-year laboratory experiment was conducted. It was found that the increase in Pb concentration of about 47% and 77% for two flour samples was consistent with the increase in annual average particulate matter with diameter 10 micrometers PM10 concentrations (55% and 82%) obtained from two stations.
The most trace metals (essential and toxic metals) in very low concentrations are needed for living organisms, especially humans, but if they exceed the recommended limit, they can lead to toxicity ...in humans. The aim of this study was to determinate of concentration of 12 trace metals including; aluminium(Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), mercury (Hg), nickel (Ni), lead (Pb) copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn), in 90 samples of sesame seeds from three varieties of black, yellow and white purchased from markets different cities of Iran (2019) using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) technique. Also, Probabilistic risk assessment (non-carcinogenic and carcinogenic risks) was estimated by models include target hazard quotient (THQ) and cancer risk (CR) in the Monte Carlo Simulation (MCS) model. The recoveries estimated from 94% to 106%. The maximum mean value was obtained for Zn element (1707 ± 22 µg kg
−1
), while concentrations of Al and Hg were non-detected (ND). The concentration of five toxic metals Al, As, Cd, Hg, and Pb as average in sesame seed samples were reported as ND, 11.464 ± 1.71, 1.15 ± 0.04, ND and 16.14 ± 1.60 μg kg
−1
, respectively. Analyzes showed that no significant difference in the amount of trace metals between sesame varieties (black, brown and white). In most of the sesame seed samples, trace metals have been measured at lower levels than the standard limits. The results of MCS showed that the rank order of toxic metals based on 95% THQ index for both adults and children was As > Cr > Pb > Ni > Cd. The uncertain analysis of human health risk (non-carcinogenic and carcinogenic risks) indicated that there is no serious risk (THQ >1 and CR >1E-4) for adults and children by ingestion of sesame seeds.
Remediation of areas contaminated by potentially toxic elements (PTE) requires the appropriate assessment of the environmental mobility of contaminants. The fractionation techniques developed for ...agrochemical and environmental purposes model the pathways of environmental mobilization mainly by sequential extraction procedures. In Europe mostly the simplified extraction scheme proposed by Community Bureau of Reference (BCR) in 1993 is widely used, why only to this certified sediment sample (BCR 701) is available, certified for fractionation of six elements (Cu, Cd, Cr, Ni, Pb, Zn). In the BCR extracts the reagent- solvents applied in leaching steps cause strong matrix interferences when for determination the PTE-contents of these solutions the multielemental capacity of inductively coupled plasma optical emission spectrometry (ICP-OES) should be utilized. Due to the different source of contamination the flexible multi-elemental ICP-OES method should be applied for analysis of the different BCR-extractant-solvent media which makes possible the reliable detection of all occurring PTE in the area. For this purpose as the most adequate solution the application of ICP-OES spectrometer with charge-coupled device (CCD)-detection was selected which is able to record the entire spectral range between 120 and 800 nm. On the basis of detailed study of BCR-solvent-matrix- and expected-analite-line interferences it was established that the sensitivities of the prominent lines of pollutant elements strongly depend on the type of extractants. For improving the accuracy of analytical results obtained for soils and environmental sediments, matrix matched calibration, internal standardization and robust plasma conditions were recommended and optimized. The successful application of this methodology is presented for a PTE-contaminated lake sediment sample and for selected typical Hungarian soil samples stored in sample bank of Hungarian Soil Protection Information and Monitoring System.
•Study of BCR-solvent-matrix- and analytical line interferences was performed.•Matrix matched calibration, internal standardization, robust plasma conditions were optimized.•Accuracy of results obtained for soils and environmental sediments can be improved by the flexible ICP-OES method.
The P‐type ATPase CrpA is an important Cu2+/Cd2+ pump in the Aspergilli, significantly contributing to the heavy metal stress tolerance of these ascomycetous fungi. As expected, the deletion of crpA ...resulted in Cu2+/Cd2+‐sensitive phenotypes in Aspergillus nidulans on stress agar plates inoculated with conidia. Nevertheless, paradoxical growth stimulations were observed with the ΔcrpA strain in both standard Cu2+ stress agar plate experiments and cellophane colony harvest (CCH) cultures, when exposed to Cd2+. These observations reflect efficient compensatory mechanisms for the loss of CrpA operating under these experimental conditions. It is remarkable that the ΔcrpA strain showed a 2.7 times higher Cd biosorption capacity in CCH cultures, which may facilitate the development of new, fungal biomass‐based bioremediation technologies to extract harmful Cd2+ ions from the environment. The nullification of crpA also significantly changed the spatial distribution of Cu and Cd in CCH cultures, as demonstrated by the combined particle‐induced X‐ray emission and scanning transmission ion microscopy technique. Most important, the centers of gravity for Cu and Cd accumulations of the ΔcrpA colonies shifted toward the older regions as compared with wild‐type surface cultures.
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