ICP-AES Research Articles

Determination of rare earth elements in ferrocarbonatite using ICP-AES and ICP-MS

AbstractA method has been developed for the determination of Rare Earth Elements (REEs) in ferrocarbonatite using Inductively Coupled Plasma—Atomic Emission Spectrometer (ICP-AES) and Inductively Coupled Plasma—Mass Spectrometer (ICP-MS). The conventional dissolution procedures are tedious, with large measurement uncertainty and are thus not suitable for certified reference material (CRM) production and exploration of REEs. The described method involves leaching of sample using 3 M HCl followed by dissolution of residue (silica and REEs) by HF then determined REEs using ICP-AES and ICP-MS. The leaching step prevents formation of fluoride precipitates of matrix (Ca, Mg, Ba and Al). The method has been validated using CRMs.

Revolutionizing sensing technologies: Crafting a green, ultra-sensitive bismuth optical sensor via fixation of 5-(2′,4′-dimethyl-phenylazo)-6-hydroxypyrimidine-2,4-dione on PVC membrane

An innovative and exceptionally responsive optical sensing device engineered to selectively identify Bi(III) ions in water-based solutions. The sensing component, 5-(2′,4′-dimethylphenylazo)-6-hydroxypyrimidine-2,4-dione (DMPAHPD), is incorporated into a plasticized polyvinyl chloride (PVC) membrane. The sensor demonstrates an exceptional selectivity for Bi(III) within a broad dynamic range spanning from 7.5 × 10−10 to 4.2 × 10−5 M at pH 2.25. Notably, it achieves lower quantification and detection limits of 7.25 × 10−10 and 2.15 × 10−10 M, respectively. The optode membrane’s response to Bi(III) proves to be entirely reversible, demonstrating remarkable selectivity for Bi(III) ions over a diverse range of other cations and anions. The sensor exhibits favorable performance characteristics, including good reversibility, a wide dynamic range, a prolonged lifespan, sustained response stability over the long term, and high reproducibility. This visual chemical sensor exhibits potential for real-world usage, offering consistent outcomes when assessing Bi(III) levels in matrices such as water, soil, plants, biological and synthetic mixtures. Importantly, the sensor’s performance is comparable to corresponding data achieved from inductively coupled plasma atomic emission spectroscopy (ICP-AES).

Tuning the toughness, strength, and biological properties of functionally graded alumina/titania-based composites for use in bone repair applications

In this study, functionally graded composite (FGC) was prepared using a high-energy ball mill by fabricating five layers of alumina (Al2O3), titania (TiO2), hydroxyapatite (HA), and iron oxide (Fe3O4), which were sintered at 1100 °C to create an FGC sample. Scanning electron microscopy (SEM), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and weight loss measurements were used to assess bioactivity and biodegradation after immersing samples in simulated body fluid (SBF). Also, the antimicrobial activity and biocompatibility of these layers were evaluated. Furthermore, their electrical, dielectric, and mechanical properties were examined. The results revealed that all sintered layers were bioactive, and adding HA and Fe3O4 enhanced this desired property. Also, S. aureus bacterial growth was inhibited by TiO2 and Fe3O4. Fortunately, the sintered layers showed no cytotoxic effect, validating the ICP findings that demonstrated acceptable biodegradation. Adding HA and Fe3O4 enhanced fracture toughness in another hopeful outcome, which is crucial for biomaterial efficacy and long-term therapeutic success. Moreover, the compressive strength of all the layers and the FGC sample was 191.7, 182.2, 171.18, 159.8, 142.5, and 171.1 MPa. Layers 3, 4, and 5 notably had a compressive strength similar to cortical bone. This means that implanting these layers into human bone will protect the bone around them from stress-shielding action. Finally, the successive increase in HA/Fe3O4 contents increased the electrical conductivity. Accordingly, the prepared FGC sample and its layers are attractive bone substitute materials.

Efficient Cu‐Based Mixed Oxides Catalyst for α‐Alkylation of Ketones with Alcohols

AbstractA series of Cu‐based mixed oxides were prepared by calcinations of corresponding CuMgAl‐layered double hydroxides precursors at different temperatures with nominal Cu/Mg/Al ratios of 1 : 1 : 2(Cu‐LDH‐1), 1 : 2 : 1(Cu‐LDH‐2),1 : 1 : 1(Cu‐LDH‐3), and 2 : 1 : 1(Cu‐LDH‐4). The synthesized catalysts were characterized using X‐ray diffraction, high‐resolution transmission electron microscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy (ICP‐AES), and N2 physisorption analysis techniques. All as‐obtained catalysts showed adequate catalytic performance for the α‐alkylation of ketones with alcohols through a hydrogen autotransfer mechanism. The catalyst CuMgAl‐I‐650 (obtained by calcining Cu‐LDH‐1 at 650 °C) displayed the highest activity and selectivity. Using this catalyst system, a wide range of branched ketones were synthesized in good to excellent isolated yields. Moreover, the catalyst CuMgAl‐I‐650 could be recycled and reutilized for four cycles without any significant loss of activity and selectivity. This study provides a very simple and inexpensive catalysis based on transition metals, which are in abundance on earth.

Developing a novel calcium silver zeolite for caries management

ObjectiveTo develop a novel calcium silver zeolite (Ca-Ag-Zeo) and assess its biocompatibility, physiochemical properties and antimicrobial effects.MethodsCa-Ag-Zeo was synthesized using ion-exchange method with calcium chloride, silver nitrate and Zeolite X (Zeo). Silver zeolite X (Ag-Zeo) and Zeo were set as control. The chemical structure, morphology, crystal structure and elemental composition of Ca-Ag-Zeo was characterized by X-ray diffraction spectrum, scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy, respectively. Its biocompatibility on the human gingival fibroblasts was assessed by cell counting kit-8 assay. Its physiochemical properties were determined by the released calcium and silver ion using Inductive Coupled Plasma Emission Spectrometry for up to 12 weeks. The antimicrobial properties on Streptococcus mutans, Lactobacillus acidophilus, Lactobacillus casei, and Candida albicans were assessed by minimum bactericidal concentration (MBC) or minimum fungicidal concentration (MFC) assay.ResultsCa-Ag-Zeo with a hexagonal cage structure was synthesized. As for biocompatibility, the half-maximal inhibitory concentration (± SD in mg/mL) of Ca-Ag-Zeo, Ag-Zeo and Zeo in human gingival fibroblasts were 0.52 ± 0.05, 0.15 ± 0.01 and 3.35 ± 0.58, respectively (Zeo > Ca-Ag-Zeo > Ag-Zeo; p < 0.05). As for physiochemical properties, the accumulated ion release (± SD in mg) of Ca-Ag-Zeo, Ag-Zeo and Zeo were 0.011 ± 0.003, 0 and 0 for calcium ion, respectively (Ca-Ag-Zeo > Ag-Zeo, Zeo; p < 0.001), and 0.213 ± 0.032, 0.209 ± 0.019 and 0 for silver ion, respectively (Ca-Ag-Zeo, Ag-Zeo > Zeo; p < 0.001). As for anti-microbial ability, the MBC/MFC (mg/mL) of Ca-Ag-Zeo, Ag-Zeo and Zeo were 32, 16 and > 256 against Streptococcus mutans; 32, 16, > 256 against Lactobacillus acidophilus; 16, 16, and 256 against Lactobacillus casei; 0.25, 0.125; and 2, 1, > 256 against Candida albicans, respectively.ConclusionA novel Ca-Ag-Zeo was developed. It presented better biocompatibility compared to Ag-Zeo. It released calcium and silver ions sustainably, and it could inhibit the growth of common cariogenic microorganisms.

Role of modified calcium montmorillonite and 5 A zeolite in microstructure and efflorescence formation of metakaolin-based geopolymer

To reduce the efflorescence extent of metakaolin (MK)-based geopolymer, this study introduced thermally activated modified calcium montmorillonite (MT) and 5 A zeolite (ZT) into MK-based geopolymer, and the optimal mixing ratio was acquired by response surface methodology. The effect of the two modified clay minerals on the microstructural and mechanical properties of the MT-ZT-MK geopolymer was explored by compressive strength testing, phase analysis (XRD and FTIR), pore structure analysis (MIP), and morphology analysis (SEM-EDS). To investigate the performance and mechanism of efflorescence inhibition of the ternary geopolymer, the cation concentration in the leaching solution was detected by inductively coupled plasma atomic emission spectrometry (ICP-OES), and the efflorescence area of the geopolymer was calculated using Image Pro Plus (IPP) software. The results of the experiment showed that the optimal mixing ratio, as determined by RSM, was 1.5 wt% of modified MT and 2.9 wt% of modified ZT, with the highest compressive strength at 65.1 MPa and the lowest degree of efflorescence after 28 days of curing. It can be concluded that the two clays gradually exhibit the effect of cation exchange and internal curing. The pore structure is optimized and (N, C)-A-S-H gels are formed with the extension of curing time. On the other hand, the lesser extent of efflorescence possibly is attributed to the restricted channels for Na+ in the matrix to undergo carbonation with CO2 in the air.

Efficacy of silver nanoparticle-modified bullfrog skin as an antimicrobial wound dressing

This research explores the synthesis of silver nanoparticles and their incorporation into bullfrog skin for potential use as a wound dressing. The study addresses the need for wound dressings that exhibit biocompatibility, low cytotoxicity, superior biodegradability, and antimicrobial activity. Silver nanoparticles were synthesized using silver nitrate and sodium citrate solutions and integrated into bullfrog skin at varying concentrations (0%, 0.5%, 1%, and 1.5%). The modified and unmodified bullfrog skin samples were characterized using dynamic light scattering(DLS), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). Antimicrobial analyses were conducted to assess the efficacy of the modified skin against common pathogens, including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. The results demonstrated that samples containing 1% and 1.5% silver nanoparticles exhibited significant inhibitory effects on all tested microorganisms. This indicates that these concentrations are optimal for antimicrobial activity, suggesting the potential of silver nanoparticle-modified bullfrog skin as an innovative and effective wound dressing material.

Mineralogical and leaching characteristics of sulfur concentrate and hot filter residue from zinc–oxygen-pressure leaching

The mineralogical properties and environmental impact of sulfur concentrate and hot filter residue produced from the zinc–oxygen-pressure leaching were studied through a series of characterization, including X-ray fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP–OES), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM–EDS), particle size distribution (PSD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and thermogravimetry and differential thermal analysis (TG–DTA). Furthermore, short-term environmental activity was assessed using the toxic leaching procedure (TCLP). The results indicated that the sulfur concentrate exhibited a coarser particle size compared with the hot filter residue, primarily appearing as spindle-shaped element sulfur (S0). The hot filter residue contained spindle-shaped S0 and rod gypsum, alongside phases of sphalerite, pyrite, and copper–silver-containing phases encapsulated by S0, recovering valuable metals first requires the removal of S0. The surfaces of both sulfur concentrate and hot filter residue were composed of S, ZnS, Al-O, PbSO4, and SiO2. They exhibited thermal instability and some degree of water absorption, with vigorous burning observed at temperatures ranging from 200 °C to 380 °C. The leachates from these materials exhibited increased concentrations of elements such as zinc, lead, and cadmium surpassing permissible limits, highlighting the importance of their safe disposal for the stable production of zinc–oxygen-pressure systems.

Analysis of Heavy Metals in Water and Wastewater

The primary focus of the study is to assess the presence and concentration of heavy metals in the water and evaluate its suitability for drinking purposes. Given that a significant portion of the local population depends on groundwater for their daily needs, the study is critical in understanding the potential health risks associated with consuming contaminated water. The study begins with a comprehensive survey to gauge the extent of water usage among the local population and their perceptions of water quality. Results from the survey reveal that nearly half of the households in the region are not connected to a formal drinking water network, relying instead on wells and springs. While the majority of respondents perceive the water quality as good, the analytical findings suggest otherwise. Groundwater samples were collected from twelve wells and three springs across the region. These samples were subjected to rigorous analysis using inductively coupled plasma-atomic emission spectrometry (ICP-AES) to detect the concentration of various heavy metals, including aluminum, silver, iron, cadmium, arsenic, chromium, cobalt, zinc, lead, and copper. The results indicate that many of these metals are present in concentrations that exceed the World Health Organization's recommended limits for safe drinking water. Iron, in particular, was found at high levels in all sampled locations, raising significant concerns. The study also employs the Heavy Metal Pollution Index (HPI) to provide a more comprehensive assessment of water quality. The HPI values calculated for the sampled water sources reveal that a majority of the wells and all of the springs have levels of heavy metal contamination that render the water non-potable. This finding is particularly alarming given the region's dependence on water, especially during periods of drought when alternative water sources are scarce.

L-cysteine mediated rapid separation of Hg2+ and MeHg+ by anion-exchange HPLC

Owing to the on-going emission of Hg into the global environment, new insight into their bioinorganic chemistry in mammals is urgently required to better understand their adverse health effects and analytical methods to quantify Hg2+ and MeHg+ in environmental samples are needed. Analytical separations can help to address both of these needs. While Hg2+ and MeHg+ have been most frequently separated by cation and reversed-phase (RP) HPLC, we here report on using anion-exchange (AEX) HPLC in conjunction with a flame atomic absorption spectrometer (FAAS) to observe the retention behavior of these mercury species in the pH range 5.0–8.0 using mobile phases comprised of 10 mM l-cysteine (Cys) in 100 mM phosphate buffer. The results obtained for pH 5.0 served as a starting point to develop a rapid HPLC separation for these mercurials. The addition of 5–20 % methanol (MeOH) to this mobile phase revealed that MeOH did not appreciably change the retention of Hg2+, but significantly reduced the retention of MeHg+. A 15 % MeOH-containing mobile phase offered the best compromise between achieving a rapid baseline separation in <400 s at affordable costs. To assess the suitability and robustness of the developed AEX-HPLC separation method for the analysis of environmental samples an inductively coupled plasma atomic emission spectrometer (ICP-AES) was employed as the mercury-specific detector. The developed AEX-HPLC-ICP-AES method allowed to achieve detection limits of 1.5 ppm for Hg2+ and 2.9 ppm for MeHg+ and was successfully applied to analyze wastewater that had been spiked with Hg2+ and MeHg+.

Chemical Composition, Antioxidant and Anti-Enzymatic Activities, and In Vitro Insecticidal Potential of Origanum compactum (Benth.) Essential Oils.

This study aimed to investigate the variation in the chemical composition of Origanum compactum essential oils (EOs) from four geographically distinct locations. Additionally, we evaluated their antioxidant properties and potential inhibitory effects on acetylcholinesterase (AChE), tyrosinase, and α-glucosidase enzymes and their insecticidal proprieties. Notably, this research also marks the first examination of the mineral composition of O. compactum. The chemical composition was determined using gas chromatography-mass spectrometry (GC-MS), which identified thymol (28.72-80.39%), carvacrol (6.54-61.84%), p-cymene (0.27-8.64%), linalool (1.44-1.96%), and caryophyllene oxide (1.34-1.56%) as the major constituents. Concurrently, inductively coupled plasma atomic emission spectroscopy (ICP-AES) revealed significant levels of macro and microelements, including calcium (295.50-512.20 mg/kg), potassium (195.99-398.45 mg/kg), magnesium (59.70-98.45 mg/kg), and iron (43.55-112.60 mg/kg). The EOs demonstrated notable antiradical activities through DPPH (1,1-diphenyl-2-picrylhydrazyl), FRAP (ferric reducing antioxidant power), and β-carotene bleaching assays. Regarding the insecticidal effect, all studied essential oils showed a significant toxicity against C. capitata adults, and the toxicity was dose and time dependent. The highest insecticidal effect was observed for O. compactum essential oils collected from Gouman (LC50 = 2.515 µL/mL, LC90 = 5.502 µL/mL) after 48 h of treatment. Furthermore, at a concentration of 1 mg/mL, the EOs exhibited strong inhibitory effects against AChE (84.75-94.01%), tyrosinase (84.75-94.01%), and α-glucosidase (79.90-87.80%), highlighting their potential as natural inhibitors of these enzymes. The essential oils of O. compactum contain components that could be used as a basis for synthetizing derivatives or analogs with potential medicinal applications and pest control properties.

A magnetic nanocatalyst based on Bronsted acid and Lewis acid centers for the efficient synthesis of polycyclic melting 1,5-benzodiazepines

In this study, 3-(Triethoxysilyl)propyl chloride (CPTES) was used to modify the surface of magnetic nanoparticles Fe3O4@SiO2, and aminomethylphosphonic acid (AMPA) was further anchored on the surface. Then, Ce (III) was used as the ligand to immobilize the surface of the modified material with N/O as the donor. Magnetic nanocatalysts (Fe3O4@SiO2@CPTES@AMPA@CeCl3) were successfully prepared. The prepared catalysts were characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen absorption-desorption experiment (BET), vibrating sample magnetometer (VSM), energy dispersive spectroscopy (EDS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). A synergetic effect of Brønsted and Lewis acid (AMPA and CeCl3) of the magnetic nanocatalyst was examined to active carbonyl, imine or enamine bonds for the synthesis of polycyclic fused 1,5-benzodiazepine with quaternary carbon centers or quinoxaline ring in a one-pot method. It was found that this catalyst exhibited excellent catalytic activities (TON up to 111368, TOF up to 110232 h−1) and high selectivities in the synthesis of fused 1,5-benzodiazepine compounds (22 examples, 85–96 % yields). The mechanism for the synthesis of polycyclic fused 1,5-benzodiazepine catalyzed by Fe3O4@SiO2@CPTES@AMPA@CeCl3 was proposed. The nanocatalyst was readily recovered by simple magnetic decantation and can be recyclable without obviously reducing catalytic activity up to seven times.

An acidless microwave-assisted wet digestion of biological samples as a greener alternative: applications from COVID-19 monitoring to plant nanobiotechnology.

Sample preparation in an analytical sequence increases the number of errors, is highly time-consuming, and involves the manipulation of hazardous reagents. Therefore, when an improvement in an analytical method is required, the sample preparation step needs to be optimised or redesigned. Moreover, this step can involve significant toxic reagents and a high volume of waste. In that regard, this study proposes a new procedure based on microwave-assisted wet digestion combining two green strategies: a miniaturised system (with a few microlitres of volume) and the only use of hydrogen peroxide. Three biological samples (human serum, urine, and plant in vitro material) were chosen due to their high potential for disease monitoring, toxicological studies, and biotechnology applications. Several trace elements (Ca, Cd, Co, Cu, Fe, Mg, Mn, Mo, Ni, Se, and Zn) were determined by inductively coupled plasma optical emission spectroscopy and inductively coupled plasma mass spectrometry. For human serum and urine, a certified reference material was used to check for accuracy; the recovery ranged from 72% (Cd, ICP-MS) to 105% (Mg, ICP OES) for serum, while for urine, they varied from 82% (Ni, ICP-MS) to 122% (Zn, ICP-MS). For the soybean callus sample (in vitro plant material), a comparison between the proposed method and the acid digestion method was conducted to evaluate the accuracy, and the results agreed. The detection limits were 0.001-60µg L-1 (lowest for Cd), thus demonstrating a suitable sensitivity. Moreover, the decomposition efficiency was demonstrated by determining the residual carbon, and a low amount was found in the final product digested (below 0.8% w v-1). A green metric approach was calculated for the proposed method, and according to AGREEprep software, it was found to be around 0.4. Finally, the method was applied to urine samples collected in patients with COVID-19 and soybean callus cultivated with silver nanoparticles. This sample preparation method is a new acidless and miniaturised alternative for elemental analysis involving biological samples.

Dual-capable spinel cobalt oxide nanoparticles for electrocatalytic oxygen evolution and water contaminant removal.

This study investigates the synthesis and electrocatalytic performance of cobalt oxide (Co3O4) nanoparticles for the oxygen evolution reaction (OER) and their role in water treatment as contaminant removal agents. Cobalt oxide nanoparticles are recognized as promising materials in electrocatalysis due to their tunable properties and nanoscale engineering potential. Here, fine cobalt oxide nanoparticles are synthesized using the sol-gel method followed by various sintering temperatures to achieve precise control over surface morphology, size, and shape. Characterization via high-resolution scanning electron microscopy (HRSEM) and high-resolution transmission electron microscopy (HRTEM) elucidates the impact of sintering temperature on nanoparticle properties. Thin film electrodes of cobalt oxide are fabricated using the doctor blade method and evaluated using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Among the tested sintering temperatures, cobalt oxide electrodes sintered at 600°C exhibit superior catalytic activity, demonstrating an overpotential of 258mV (vs RHE) at 10mAcm-2 current density and a Tafel slope of 17.33mV dec-1. Furthermore, these electrodes demonstrate excellent stability, maintaining OER performance for 10h in 1M NaOH electrolyte. Additionally, the role of cobalt oxide nanoparticles in water treatment is explored using inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental results reveal that lower sintering temperatures enhance the electrocatalytic properties of cobalt oxide nanoparticles, highlighting their potential contribution to sustainable energy and water treatment technologies. This work underscores the significance of cobalt oxide nanoparticles as dual-functional materials for advancing electrocatalysis and water purification applications, thus paving the way for the development of efficient and environmentally friendly technologies.

Lithochemistry, and gold and sulphides chemistry from the Abiete-Toko Gold District in the NW edge Congo Craton, Nyong Complex (SW-Cameroon): Insights into the primary source of alluvial gold deposits and occurrence in the area

The Abiete-Toko Gold District (ATGD), in the Nyong Complex, NW edge of the Congo Craton, is one of the numerous Cameroonian mining districts producing alluvial gold. Although numerous works were focused on the ATGD alluvial gold deposits, their primary source(s) remain(s) unknown. This study combines the chemistry of pyrite and chalcopyrite which were determined by inductively coupled plasma-mass spectrometry (LA-ICP-MS), the chemistry of alluvial gold grains determined by electron probe microanalysis (EPMA), and whole rock composition determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results provide the first evidence of gold in the rocks, and its genesis is subsequently discussed. Gold in the ATGD rocks is essentially invisible and lattice bound in pyrite and chalcopyrite, which intake up to 3.11 ppm and up to 32.6 ppm Au, respectively. The gold-bearing metatexites (garnet migmatite) and ultrabasites (serpentinised peridotites) are here therefore, interpreted as possible sources of the ATGD alluvial gold deposits and occurrences. In metatexite, pyrite and chalcopyrite occur within quartz biotite veins, while in ultrabasites pyrite and chalcopyrite are disseminated grains of millimetric sizes, and ovoid or cubic shapes. Gold mineralisation is shear-hosted and, shows evidence of hydrothermal alteration (sulphidation) induced by circulating magmatic and Co-rich (0.01–1.53 %) fluids.

The analysis of the essential metal contents in khat (Catha edulis Forsk) from Meru County, Kenya

BackgroundChemical composition of plants has attracted considerable interest in recent years with considerable research tailored into determining metal contents in food substances. Particularly, essential elements which are necessary for normal human body functioning and are strongly recommended in optimal proportions for better health. This study determined the levels of essential elements; calcium (Ca), magnesium (Mg), sodium (Na), potassium (K) and manganese (Mn) in eleven khat (Catha edulis Forsk) samples collected from Meru County. Methodology1.0 g of dry ground khat samples were wet-digested in a solvent mixture of 10 mL of HCl, HNO3 and 20 vol of H2O2 for 3 h at variable temperature of 50–90 °C and later reconstituted in 25 mL 0.05 molL−1 HCl before analysis. The samples were analyzed using inductively coupled plasma atomic emission spectrometry (ICP AES) after acid digestion whereas Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to investigate elemental characteristics and determine the sources of essential metals in khat. In addition, Pearson correlation coefficient (PCC) was used to evaluate the relationships between the essential metals. ResultsSpinach leaves certified reference material (CRM 1750a) was analyzed and the percentage recoveries (%) of 98.4 and 101.7 determined showing that the digestion method employed in this work had adequate accuracy. The validated method was employed for the analysis of all the khat samples. The analyzed metal concentration ranges (mg100g−1) in fresh-weight basis per day of five metals were 160.9–267.3, 44.6–81.7, 2.0–3.0, 237.6–393.6, and 220.3 -349.0 for Ca, Mg, Mn, K, and Na, respectively. Both HCA and PCA results showed that these elements could be linked to natural soils and anthropogenic sources. PCC reported significant correlations between Na and K indicating they may have been derived from the same source. The daily metal intakes were below the World Health Organization (WHO) permissible limits implying no associated health risks for khat users. ConclusionBased on the findings of this study, the consumption of khat from regions of Meru County may be a potential source for essential elements required for human biological processes.

Aqueous Lithium-Ion Battery with Dual Electrolytes at Equilibrium across Cation-Exchange Membrane Separator

Aqueous lithium-ion batteries (ALIBs) have been investigated as a promising safe and low-cost storage device for sustainable energy. For the stability of ALIBs, it is important to expand the electrochemical stability window of aqueous electrolytes. Although “Water-in-salt” electrolytes [1] containing significant amounts of lithium salts have been reported as an effective approach, cost reduction of the aqueous electrolyte remains a major challenge for the industrialization of such ALIBs.Controlling the pH of the aqueous electrolyte is another approach to widen the electrochemical window with a smaller use of lithium salts. The 2 V-class ALIB of Zn-coated Li4Ti5O12/LiMn2O4 was demonstrated using dual aqueous electrolytes having different pH separated by a lithium-ion conductive inorganic solid electrolyte.[2] However, lithium-ion conductive inorganic solid electrolytes may often be unstable in alkaline solutions. A perfluorinated sulfonic acid cation-exchange membrane (CEM) is one of the possible alternatives for separating two different aqueous electrolytes. In principle, the concentration of the entire electrolyte does not change during lithium-ion battery operation where lithium ions shuttle between the cathode and anode. Therefore, the specific compositions of the cathode and anode electrolytes are selected to achieve the Donnan equilibrium across the CEM, and stable battery operation is expected as long as the electrolyte equilibrium is maintained. In this study, the feasibility of this concept was investigated using ALIB cell of the anatase-TiO2/spinel-LiMn2O4.A stable combination of cathode and anode electrolytes was investigated experimentally. Several compositions of cathode and anode electrolytes were prepared, and equal volumes of the cathode and anode electrolytes were faced across the CEM, stored for 10 days at room temperature, and the composition of each electrolyte were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). After repeating this procedure, a stable combination of cathode and anode electrolytes was found as 27 g/L of Li and 8 g/L of K for an anode electrolyte, and 24 g/L of Li, 36 g/L of K, 41 g/L of P, and 68 g/L of S for a cathode electrolyte prepared using LiOH, KOH, Li2SO4, and KH2PO4. The pH was 4 and 11 for the cathode and anode electrolytes, respectively.The battery test was demonstrated for the TiO2/LiMn2O4 cells assembled with the cathode/anode electrolyte and the same 2 mol/kg Li2SO4 electrolyte in both sides for comparison. The initial charge/discharge profiles are shown in Fig. 1. The profiles were obtained by constant current of 15 mA/g regarding the weight of the cathode active material with the cutoff voltage of 2.8 V and 1.5 V in charge and discharge processes, respectively. The Coulombic efficiency was reached to 96% in the cells with electrolytes having the pH difference, whereas it was 69% in the cell with the 2 mol/kg Li2SO4. The alkaline anode electrolyte suppressed hydrogen generation sufficiently for the lithiation/delithiation of anatase TiO2, which leads to an excellent reversibility over 2 V operation with an improvement in the Coulombic efficiency of the cell with dual aqueous electrolytes.To further investigate the stability of the aqueous battery, a cycle test was conducted on the cell with the dual electrolytes. Figure 1(b) shows the discharge capacity during 100 charge-discharge cycles obtained by the constant current of 75 mA/g-cathode. The Coulombic efficiency reached >99%, and the capacity retention was calculated to be 75% at 100 cycles, which indicates that the suitable pH of the cathode and anode electrolyte was maintained during repeated charge/discharge cycles.In the presentation, we will discuss the details of the battery operation, including a role of perfluorosulfonated CEM and issues to improve the battery performance.

Corrosion Behavior of 3104 Aluminum Cans When Used as Packaging for Chinese Liquor.

Aluminum cans are commonly used for packaging soft drinks and low-alcohol beverages due to their good recyclability. To enhance the economic cycle and expand the packaging of liquors, the feasibility of commercial 3104 aluminum cans for packaging Chinese liquor was studied. The aluminum's migration into alcoholic solutions was studied using inductively coupled plasma emission spectroscopy (ICP-OES). Electrochemical impedance spectroscopy (EIS) was used to study the corrosion process of epoxy coatings on the aluminum cans. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), infrared attenuated total reflection (IR-ATR), and X-ray diffraction (XRD) were used to determine the inner coatings and adhering surfaces of the cans and the corrosion process. The results showed that the maximum aluminum migration in Chinese liquor was 4.3572 mg/kg at 60 °C for 30 days. The epoxy coating was corroded enough to decrease the coating impedance and expose the metal substrate after 25 days. Permeation and aging degradation of coatings are the main factors to consider when packaging liquor.

Use of lichens as bioindicators of contamination by agrochemicals and metals.

The presence or absence of lichens serves as an indicator of the condition of an ecosystem and the degree to which it is contaminated by various agents, such as agrochemicals and metals. Evaluating the use of lichens as bioindicators of agrochemical contamination could provide a more comprehensive perspective of current contamination levels. Monitoring was conducted over a 4-month period in two study areas: one was a well-conserved area contaminated by metals, and the other was an area surrounded by agricultural crops contaminated by agrochemicals. Data on the presence and abundance of lichens in each study area were recorded at 10 monitoring points, a procedure that was repeated 16 times (every 15days), and concentrations of heavy metals and "organophosphate" agrochemicals in the lichens collected were measured by means of Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES) and Gas Chromatography (GC), respectively. Generalized linear mixed models were used to assess abundance and richness, while general linear mixed models were used to attain Shannon diversity and Simpson dominance indices. Moreover, a multivariate analysis was performed in order to compare the lichen communities in both areas. The results indicated differences between the area contaminated by metals and that contaminated by agrochemicals in terms of abundance and Simpson's dominance index, while no differences were found in the case of the richness and diversity models. The PERMANOVA analysis additionally showed differences between the lichen communities in the two areas. The results also demonstrated that Canoparmelia caroliniana bioaccumulated metals in both areas. The levels of barium, cadmium, and sodium were higher in the area contaminated by metals, while concentrations of chromium and copper were higher in the area contaminated by agrochemicals. Finally, the concentrations of agrochemicals were higher in the area contaminated by agrochemicals and included toxic substances such as Methylparathion and Parathion, which are prohibited in Ecuador. In conclusion, this research underscores the importance of lichens as precise indicators of environmental health and contamination by agrochemicals and metals.

AB015. Efficacy and safety of boron neutron capture therapy in managing metastatic spinal tumors: experimental findings.

Boron neutron capture therapy (BNCT) is a unique cancer treatment modality that enables precise targeting of tumors at the cellular level. Based on the success observed in nuclear reactors, BNCT now holds promise as a therapeutic approach for treating invasive brain tumors or head and neck cancers. Metastatic spinal tumors have been treated with multidisciplinary interventions such as surgical resection and radiation therapy. Despite recent advantages of radiation therapy, it remains challenging to achieve better quality of life and activity of daily living. The purpose of this study was to evaluate the efficacy and safety of BNCT in metastatic spinal tumor using a mouse model. For the in vitro, neutron and photon irradiation was applied to A549 human lung adenocarcinoma cells. The cells were irradiated neutrons with or without p-boronophenylalanine (BPA) 10 µg Boron/mL for a 24-h exposure before neutron irradiation. The difference of biological effect between neutrons and photons was evaluated by colony forming assay. For in vivo, the tumor-bearing mice were intravenously administered BPA (250 mg/kg), followed by measuring biodistribution of boron using inductively coupled plasma atomic emission spectroscopy (ICP-AES). For in vivo BNCT, the mice were randomly assigned to untreated (n=10), neutron irradiation only (n=9), and BNCT groups (n=10). Overall survival and hindlimb function were analyzed. Histopathological examination was also performed to assess the influences of neutron irradiation. Neutron irradiation showed a stronger cell-killing effect than that exhibited by photon irradiation in vitro. For in vivo biodistribution, the highest boron accumulation in the tumor was seen at 2.5-h time point (10.5 µg B/g), with a tumor to normal spinal cord and blood ratios were 3.6 and 2.9, respectively. For the in vivo BNCT, BNCT had significantly prolonged survival (vs. untreated, P=0.002; vs. neutron only, P=0.01, respectively, log-rank test) and preserved mice hindlimb function compared to the other groups (vs. untreated, P<0.001; vs. neutron only, P=0.005, respectively, MANOVA). No adverse events and apparent histopathological changes were observed among three groups. These findings indicate that BNCT may represent a novel therapeutic option in the management of metastatic spinal tumors.